diff --git a/src/Directory.Build.props b/src/Directory.Build.props
index 00b70293..d944f19f 100644
--- a/src/Directory.Build.props
+++ b/src/Directory.Build.props
@@ -18,6 +18,10 @@
         <PackageIconUrl>https://github.com/testcontainers/Docker.DotNet/raw/main/icon.png</PackageIconUrl>
     </PropertyGroup>
 
+    <PropertyGroup>
+      <Nullable>enable</Nullable>
+    </PropertyGroup>
+
     <PropertyGroup Condition="'$(GITHUB_ACTIONS)' == 'true'">
         <ContinuousIntegrationBuild>true</ContinuousIntegrationBuild>
     </PropertyGroup>
diff --git a/src/Docker.DotNet.Handler.Abstractions/Docker.DotNet.Handler.Abstractions.csproj b/src/Docker.DotNet.Handler.Abstractions/Docker.DotNet.Handler.Abstractions.csproj
index ba251a6f..5ba5c828 100644
--- a/src/Docker.DotNet.Handler.Abstractions/Docker.DotNet.Handler.Abstractions.csproj
+++ b/src/Docker.DotNet.Handler.Abstractions/Docker.DotNet.Handler.Abstractions.csproj
@@ -4,9 +4,6 @@
     <PackageId>Docker.DotNet.Enhanced.Handler.Abstractions</PackageId>
     <Description>An abstraction layer for Docker.DotNet that defines the classes and interfaces for implementing Docker Engine handlers.</Description>
   </PropertyGroup>
-  <PropertyGroup>
-    <Nullable>enable</Nullable>
-  </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" />
   </ItemGroup>
diff --git a/src/Docker.DotNet.X509/CertificateCredentials.cs b/src/Docker.DotNet.X509/CertificateCredentials.cs
index d72efbd8..9e4e09f5 100644
--- a/src/Docker.DotNet.X509/CertificateCredentials.cs
+++ b/src/Docker.DotNet.X509/CertificateCredentials.cs
@@ -11,7 +11,7 @@ public CertificateCredentials(X509Certificate2 certificate)
 
     public bool TlsEnabled => true;
 
-    public RemoteCertificateValidationCallback ServerCertificateValidationCallback { get; set; }
+    public RemoteCertificateValidationCallback? ServerCertificateValidationCallback { get; set; }
 
     public HttpMessageHandler ConfigureHandler(HttpMessageHandler handler)
     {
@@ -35,7 +35,10 @@ public HttpMessageHandler ConfigureHandler(HttpMessageHandler handler)
                 httpHandler.ClientCertificates.Add(_certificate);
             }
 
-            httpHandler.ServerCertificateCustomValidationCallback = (message, certificate, chain, sslPolicyErrors) => ServerCertificateValidationCallback(message, certificate, chain, sslPolicyErrors);
+            if (ServerCertificateValidationCallback is { } serverCertificateValidationCallback)
+            {
+                httpHandler.ServerCertificateCustomValidationCallback = (message, certificate, chain, sslPolicyErrors) => serverCertificateValidationCallback(message, certificate, chain, sslPolicyErrors);
+            }
             return httpHandler;
         }
 #endif
diff --git a/src/Docker.DotNet/Docker.DotNet.csproj b/src/Docker.DotNet/Docker.DotNet.csproj
index dcc00047..da5c71ad 100644
--- a/src/Docker.DotNet/Docker.DotNet.csproj
+++ b/src/Docker.DotNet/Docker.DotNet.csproj
@@ -4,9 +4,6 @@
     <PackageId>Docker.DotNet.Enhanced</PackageId>
     <Description>A .NET client for the Docker Engine API with fully asynchronous, non-blocking, object-oriented APIs.</Description>
   </PropertyGroup>
-  <PropertyGroup>
-    <Nullable>enable</Nullable>
-  </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" />
   </ItemGroup>
diff --git a/src/Docker.DotNet/EnumerableQueryStringConverter.cs b/src/Docker.DotNet/EnumerableQueryStringConverter.cs
index 262eb83f..1558ccd3 100644
--- a/src/Docker.DotNet/EnumerableQueryStringConverter.cs
+++ b/src/Docker.DotNet/EnumerableQueryStringConverter.cs
@@ -7,7 +7,7 @@ internal class EnumerableQueryStringConverter : IQueryStringConverter
 {
     public bool CanConvert(Type t)
     {
-        return typeof (IEnumerable).GetTypeInfo().IsAssignableFrom(t.GetTypeInfo());
+        return typeof(IEnumerable).GetTypeInfo().IsAssignableFrom(t.GetTypeInfo());
     }
 
     public string[] Convert(object o)
@@ -16,12 +16,12 @@ public string[] Convert(object o)
         Debug.Assert(o is IEnumerable);
 
         var items = new List<string>();
-        foreach (var e in ((IEnumerable) o))
+        foreach (var e in (IEnumerable)o!)
         {
             if (e is ValueType ||
                 e is string)
             {
-                items.Add(e.ToString());
+                items.Add(e.ToString()!);
             }
             else
             {
diff --git a/src/Docker.DotNet/JsonEnumMemberConverter.cs b/src/Docker.DotNet/JsonEnumMemberConverter.cs
index 8b92af6e..0730ffe1 100644
--- a/src/Docker.DotNet/JsonEnumMemberConverter.cs
+++ b/src/Docker.DotNet/JsonEnumMemberConverter.cs
@@ -5,7 +5,7 @@ internal sealed class JsonEnumMemberConverter<TEnum> : JsonConverter<TEnum> wher
     private readonly Dictionary<string, string> _enumFields = typeof(TEnum).GetFields(BindingFlags.Public | BindingFlags.Static)
         .Select(field => (Name: field.Name, Attribute: field.GetCustomAttribute<EnumMemberAttribute>()))
         .Where(item => item.Attribute != null && item.Attribute.Value != null)
-        .ToDictionary(item => item.Name, item => item.Attribute.Value);
+        .ToDictionary(item => item.Name, item => item.Attribute!.Value!);
 
     public override TEnum Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
     {
diff --git a/src/Docker.DotNet/JsonSerializer.cs b/src/Docker.DotNet/JsonSerializer.cs
index 30ca2c29..87e11f9b 100644
--- a/src/Docker.DotNet/JsonSerializer.cs
+++ b/src/Docker.DotNet/JsonSerializer.cs
@@ -48,12 +48,12 @@ public byte[] SerializeToUtf8Bytes<T>(T value)
 
     public T Deserialize<T>(byte[] json)
     {
-        return System.Text.Json.JsonSerializer.Deserialize<T>(json, _options);
+        return System.Text.Json.JsonSerializer.Deserialize<T>(json, _options)!;
     }
 
     public Task<T> DeserializeAsync<T>(HttpContent content, CancellationToken cancellationToken)
     {
-        return content.ReadFromJsonAsync<T>(_options, cancellationToken);
+        return content.ReadFromJsonAsync<T>(_options, cancellationToken)!;
     }
 
     public async IAsyncEnumerable<T> DeserializeAsync<T>(Stream stream, [EnumeratorCancellation] CancellationToken cancellationToken)
@@ -69,7 +69,7 @@ public async IAsyncEnumerable<T> DeserializeAsync<T>(Stream stream, [EnumeratorC
 
             while (!buffer.IsEmpty && TryParseJson(ref buffer, out var jsonDocument))
             {
-                yield return jsonDocument.Deserialize<T>(_options);
+                yield return jsonDocument!.Deserialize<T>(_options)!;
             }
 
             if (result.IsCompleted)
@@ -83,7 +83,7 @@ public async IAsyncEnumerable<T> DeserializeAsync<T>(Stream stream, [EnumeratorC
         await reader.CompleteAsync();
     }
 
-    private static bool TryParseJson(ref ReadOnlySequence<byte> buffer, out JsonDocument jsonDocument)
+    private static bool TryParseJson(ref ReadOnlySequence<byte> buffer, out JsonDocument? jsonDocument)
     {
         var reader = new Utf8JsonReader(buffer, isFinalBlock: false, default);
 
diff --git a/src/Docker.DotNet/Models/ObjectExtensionData.cs b/src/Docker.DotNet/Models/ObjectExtensionData.cs
index 9ab55629..3933f08c 100644
--- a/src/Docker.DotNet/Models/ObjectExtensionData.cs
+++ b/src/Docker.DotNet/Models/ObjectExtensionData.cs
@@ -3,5 +3,5 @@ namespace Docker.DotNet.Models;
 public class ObjectExtensionData
 {
     [JsonExtensionData]
-    public IDictionary<string, object> ExtensionData { get; set; }
+    public IDictionary<string, object>? ExtensionData { get; set; }
 }
\ No newline at end of file
diff --git a/src/Docker.DotNet/QueryString.cs b/src/Docker.DotNet/QueryString.cs
index b2a750a0..f13a4c45 100644
--- a/src/Docker.DotNet/QueryString.cs
+++ b/src/Docker.DotNet/QueryString.cs
@@ -4,7 +4,7 @@ internal class QueryString<T> : IQueryString where T : class
 {
     private T Object { get; }
 
-    private Tuple<PropertyInfo, QueryStringParameterAttribute>[] AttributedPublicProperties { get; }
+    private Dictionary<PropertyInfo, QueryStringParameterAttribute> AttributedPublicProperties { get; }
 
     private IQueryStringConverterInstanceFactory QueryStringConverterInstanceFactory { get; }
 
@@ -25,8 +25,8 @@ public IDictionary<string, string[]> GetKeyValuePairs()
         var queryParameters = new Dictionary<string, string[]>();
         foreach (var pair in AttributedPublicProperties)
         {
-            var property = pair.Item1;
-            var attribute = pair.Item2;
+            var property = pair.Key;
+            var attribute = pair.Value;
             var value = property.GetValue(Object, null);
 
             // 'Required' check
@@ -43,12 +43,12 @@ public IDictionary<string, string[]> GetKeyValuePairs()
                 string[] valueStr;
                 if (attribute.ConverterType == null)
                 {
-                    valueStr = new[] { value.ToString() };
+                    valueStr = [value!.ToString()!];
                 }
                 else
                 {
                     var converter = QueryStringConverterInstanceFactory.GetConverterInstance(attribute.ConverterType);
-                    valueStr = ConvertValue(converter, value);
+                    valueStr = ConvertValue(converter, value!);
 
                     if (valueStr == null)
                     {
@@ -76,7 +76,7 @@ public string GetQueryString()
                         v => $"{Uri.EscapeDataString(pair.Key)}={Uri.EscapeDataString(v)}"))));
     }
 
-    private string[] ConvertValue(IQueryStringConverter converter, object value)
+    private static string[] ConvertValue(IQueryStringConverter converter, object value)
     {
         if (!converter.CanConvert(value.GetType()))
         {
@@ -86,30 +86,33 @@ private string[] ConvertValue(IQueryStringConverter converter, object value)
         return converter.Convert(value);
     }
 
-    private Tuple<PropertyInfo, TAttribType>[] FindAttributedPublicProperties<TValue, TAttribType>() where TAttribType : Attribute
+    private static Dictionary<PropertyInfo, TAttribType> FindAttributedPublicProperties<TValue, TAttribType>() where TAttribType : Attribute
     {
         var t = typeof(TValue);
-        var ofAttributeType = typeof(TAttribType);
+        Dictionary<PropertyInfo, TAttribType>? attributedPublicProperties = null;
 
-        var properties = t.GetProperties();
-        var publicProperties = properties.Where(p => p.GetGetMethod(false).IsPublic);
-        if (!publicProperties.Any())
+        foreach (var prop in t.GetProperties())
         {
-            throw new InvalidOperationException($"No public property getters found on type {t.FullName}.");
+            if (prop.GetGetMethod(false)?.IsPublic == true)
+            {
+                var attribute = prop.GetCustomAttribute<TAttribType>();
+                if (attribute != null)
+                {
+                    attributedPublicProperties ??= new Dictionary<PropertyInfo, TAttribType>();
+                    attributedPublicProperties.Add(prop, attribute);
+                }
+            }
         }
 
-        var attributedPublicProperties = properties.Where(p => p.GetCustomAttribute<TAttribType>() != null).ToArray();
-        if (!attributedPublicProperties.Any())
+        if (attributedPublicProperties == null)
         {
-            throw new InvalidOperationException(
-                $"No public properties attributed with [{ofAttributeType.FullName}] found on type {t.FullName}.");
+            throw new InvalidOperationException($"No public properties attributed with [{typeof(TAttribType).FullName}] found on type {t.FullName}.");
         }
 
-        return attributedPublicProperties.Select(pi =>
-            new Tuple<PropertyInfo, TAttribType>(pi, pi.GetCustomAttribute<TAttribType>())).ToArray();
+        return attributedPublicProperties;
     }
 
-    private static bool IsDefaultOfType(object o)
+    private static bool IsDefaultOfType(object? o)
     {
         if (o is ValueType)
         {
diff --git a/src/Microsoft.Net.Http.Client/BufferedReadStream.cs b/src/Microsoft.Net.Http.Client/BufferedReadStream.cs
index 64357bb8..72c67968 100644
--- a/src/Microsoft.Net.Http.Client/BufferedReadStream.cs
+++ b/src/Microsoft.Net.Http.Client/BufferedReadStream.cs
@@ -4,7 +4,7 @@ internal sealed class BufferedReadStream : WriteClosableStream, IPeekableStream
 {
     private readonly Stream _inner;
 
-    private readonly Socket _socket;
+    private readonly Socket? _socket;
 
     private readonly byte[] _buffer;
 
@@ -16,14 +16,14 @@ internal sealed class BufferedReadStream : WriteClosableStream, IPeekableStream
 
     private int _bufferCount;
 
-    private MemoryStream _readLineBuffer;
+    private MemoryStream? _readLineBuffer;
 
-    public BufferedReadStream(Stream inner, Socket socket, ILogger logger)
+    public BufferedReadStream(Stream inner, Socket? socket, ILogger logger)
         : this(inner, socket, 8192, logger)
     {
     }
 
-    public BufferedReadStream(Stream inner, Socket socket, int bufferLength, ILogger logger)
+    public BufferedReadStream(Stream inner, Socket? socket, int bufferLength, ILogger logger)
     {
         _inner = inner ?? throw new ArgumentNullException(nameof(inner));
         _socket = socket;
@@ -146,7 +146,7 @@ public bool Peek(byte[] buffer, uint toPeek, out uint peeked, out uint available
         throw new NotSupportedException("_inner stream isn't a peekable stream");
     }
 
-    public async Task<string> ReadLineAsync(CancellationToken cancellationToken)
+    public async Task<string?> ReadLineAsync(CancellationToken cancellationToken)
     {
         if (_readLineBuffer == null)
         {
diff --git a/src/Microsoft.Net.Http.Client/HttpConnection.cs b/src/Microsoft.Net.Http.Client/HttpConnection.cs
index fb8c1ab2..aec07719 100644
--- a/src/Microsoft.Net.Http.Client/HttpConnection.cs
+++ b/src/Microsoft.Net.Http.Client/HttpConnection.cs
@@ -126,7 +126,7 @@ private async Task<List<string>> ReadResponseLinesAsync(CancellationToken cancel
                 break;
             }
 
-            lines.Add(line);
+            lines.Add(line!);
         }
         while (true);
 
diff --git a/src/Microsoft.Net.Http.Client/HttpConnectionResponseContent.cs b/src/Microsoft.Net.Http.Client/HttpConnectionResponseContent.cs
index 985e7f61..4fbaefc2 100644
--- a/src/Microsoft.Net.Http.Client/HttpConnectionResponseContent.cs
+++ b/src/Microsoft.Net.Http.Client/HttpConnectionResponseContent.cs
@@ -3,7 +3,7 @@ namespace Microsoft.Net.Http.Client;
 public class HttpConnectionResponseContent : HttpContent
 {
     private readonly HttpConnection _connection;
-    private Stream _responseStream;
+    private Stream? _responseStream;
 
     internal HttpConnectionResponseContent(HttpConnection connection)
     {
@@ -40,21 +40,21 @@ public WriteClosableStream HijackStream()
         return _connection.Transport;
     }
 
-    protected override Task SerializeToStreamAsync(Stream stream, TransportContext context)
+    protected override Task SerializeToStreamAsync(Stream stream, TransportContext? context)
     {
-        return _responseStream.CopyToAsync(stream);
+        return _responseStream!.CopyToAsync(stream);
     }
 
 #if NET6_0_OR_GREATER
-    protected override Task SerializeToStreamAsync(Stream stream, TransportContext context, CancellationToken cancellationToken)
+    protected override Task SerializeToStreamAsync(Stream stream, TransportContext? context, CancellationToken cancellationToken)
     {
-        return _responseStream.CopyToAsync(stream, cancellationToken);
+        return _responseStream!.CopyToAsync(stream, cancellationToken);
     }
 #endif
 
     protected override Task<Stream> CreateContentReadStreamAsync()
     {
-        return Task.FromResult(_responseStream);
+        return Task.FromResult(_responseStream!);
     }
 
     protected override bool TryComputeLength(out long length)
@@ -69,7 +69,7 @@ protected override void Dispose(bool disposing)
         {
             if (disposing)
             {
-                _responseStream.Dispose();
+                _responseStream?.Dispose();
                 _connection.Dispose();
             }
         }
diff --git a/src/Microsoft.Net.Http.Client/ManagedHandler.cs b/src/Microsoft.Net.Http.Client/ManagedHandler.cs
index 17131920..cd0f87cb 100644
--- a/src/Microsoft.Net.Http.Client/ManagedHandler.cs
+++ b/src/Microsoft.Net.Http.Client/ManagedHandler.cs
@@ -4,11 +4,11 @@ public class ManagedHandler : HttpMessageHandler
 {
     private readonly ILogger _logger;
 
-    private readonly StreamOpener _streamOpener;
+    private readonly StreamOpener? _streamOpener;
 
-    private readonly SocketOpener _socketOpener;
+    private readonly SocketOpener? _socketOpener;
 
-    private IWebProxy _proxy;
+    private IWebProxy? _proxy;
 
     public delegate Task<Stream> StreamOpener(string host, int port, CancellationToken cancellationToken);
 
@@ -32,7 +32,7 @@ public ManagedHandler(SocketOpener opener, ILogger logger)
         _socketOpener = opener ?? throw new ArgumentNullException(nameof(opener));
     }
 
-    public IWebProxy Proxy
+    public IWebProxy? Proxy
     {
         get
         {
@@ -55,7 +55,7 @@ public IWebProxy Proxy
 
     public RedirectMode RedirectMode { get; set; } = RedirectMode.NoDowngrade;
 
-    public RemoteCertificateValidationCallback ServerCertificateValidationCallback { get; set; }
+    public RemoteCertificateValidationCallback? ServerCertificateValidationCallback { get; set; }
 
     public X509CertificateCollection ClientCertificates { get; set; } = new X509Certificate2Collection();
 
@@ -66,7 +66,7 @@ protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage
             throw new ArgumentNullException(nameof(httpRequestMessage));
         }
 
-        HttpResponseMessage httpResponseMessage = null;
+        HttpResponseMessage? httpResponseMessage = null;
 
         for (var i = 0; i < MaxAutomaticRedirects; i++)
         {
@@ -81,7 +81,7 @@ protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage
             }
         }
 
-        return httpResponseMessage;
+        return httpResponseMessage!;
     }
 
     private bool IsRedirectResponse(HttpRequestMessage request, HttpResponseMessage response)
@@ -142,20 +142,24 @@ private async Task<HttpResponseMessage> ProcessRequestAsync(HttpRequestMessage r
         request.Headers.ConnectionClose = !request.Headers.Contains("Connection"); // TODO: Connection reuse is not supported.
 
         ProxyMode proxyMode = DetermineProxyModeAndAddressLine(request);
-        Socket socket;
+        Socket? socket;
         Stream transport;
 
         try
         {
             if (_socketOpener != null)
             {
-                socket = await _socketOpener(request.GetConnectionHostProperty(), request.GetConnectionPortProperty().Value, cancellationToken).ConfigureAwait(false);
+                socket = await _socketOpener(request.GetConnectionHostProperty()!, request.GetConnectionPortProperty()!.Value, cancellationToken).ConfigureAwait(false);
                 transport = new NetworkStream(socket, true);
             }
-            else
+            else if (_streamOpener != null)
             {
                 socket = null;
-                transport = await _streamOpener(request.GetConnectionHostProperty(), request.GetConnectionPortProperty().Value, cancellationToken).ConfigureAwait(false);
+                transport = await _streamOpener(request.GetConnectionHostProperty()!, request.GetConnectionPortProperty()!.Value, cancellationToken).ConfigureAwait(false);
+            }
+            else
+            {
+                throw new Exception("Missing socketOpener or streamOpener");
             }
         }
         catch (SocketException e)
@@ -171,7 +175,7 @@ private async Task<HttpResponseMessage> ProcessRequestAsync(HttpRequestMessage r
         if (request.IsHttps())
         {
             SslStream sslStream = new SslStream(transport, false, ServerCertificateValidationCallback);
-            await sslStream.AuthenticateAsClientAsync(request.GetHostProperty(), ClientCertificates, SslProtocols.Tls12, false);
+            await sslStream.AuthenticateAsClientAsync(request.GetHostProperty()!, ClientCertificates, SslProtocols.Tls12, false);
             transport = sslStream;
         }
 
@@ -183,10 +187,10 @@ private async Task<HttpResponseMessage> ProcessRequestAsync(HttpRequestMessage r
     // Data comes from either the request.RequestUri or from the request.Properties
     private static void ProcessUrl(HttpRequestMessage request)
     {
-        string scheme = request.GetSchemeProperty();
+        string? scheme = request.GetSchemeProperty();
         if (string.IsNullOrWhiteSpace(scheme))
         {
-            if (!request.RequestUri.IsAbsoluteUri)
+            if (!request.RequestUri!.IsAbsoluteUri)
             {
                 throw new InvalidOperationException("Missing URL Scheme");
             }
@@ -196,13 +200,13 @@ private static void ProcessUrl(HttpRequestMessage request)
 
         if (!request.IsHttp() && !request.IsHttps())
         {
-            throw new InvalidOperationException("Only HTTP or HTTPS are supported, not: " + request.RequestUri.Scheme);
+            throw new InvalidOperationException("Only HTTP or HTTPS are supported, not: " + request.RequestUri?.Scheme);
         }
 
-        string host = request.GetHostProperty();
+        string? host = request.GetHostProperty();
         if (string.IsNullOrWhiteSpace(host))
         {
-            if (!request.RequestUri.IsAbsoluteUri)
+            if (!request.RequestUri!.IsAbsoluteUri)
             {
                 throw new InvalidOperationException("Missing URL Scheme");
             }
@@ -210,7 +214,7 @@ private static void ProcessUrl(HttpRequestMessage request)
             request.SetHostProperty(host);
         }
 
-        string connectionHost = request.GetConnectionHostProperty();
+        string? connectionHost = request.GetConnectionHostProperty();
         if (string.IsNullOrWhiteSpace(connectionHost))
         {
             request.SetConnectionHostProperty(host);
@@ -219,7 +223,7 @@ private static void ProcessUrl(HttpRequestMessage request)
         int? port = request.GetPortProperty();
         if (!port.HasValue)
         {
-            if (!request.RequestUri.IsAbsoluteUri)
+            if (!request.RequestUri!.IsAbsoluteUri)
             {
                 throw new InvalidOperationException("Missing URL Scheme");
             }
@@ -233,10 +237,10 @@ private static void ProcessUrl(HttpRequestMessage request)
             request.SetConnectionPortProperty(port);
         }
 
-        string pathAndQuery = request.GetPathAndQueryProperty();
+        string? pathAndQuery = request.GetPathAndQueryProperty();
         if (string.IsNullOrWhiteSpace(pathAndQuery))
         {
-            if (request.RequestUri.IsAbsoluteUri)
+            if (request.RequestUri!.IsAbsoluteUri)
             {
                 pathAndQuery = request.RequestUri.PathAndQuery;
             }
@@ -252,9 +256,9 @@ private static void ProcessHostHeader(HttpRequestMessage request)
     {
         if (string.IsNullOrWhiteSpace(request.Headers.Host))
         {
-            string host = request.GetHostProperty();
-            int port = request.GetPortProperty().Value;
-            if (host.Contains(':'))
+            string? host = request.GetHostProperty();
+            int port = request.GetPortProperty()!.Value;
+            if (host?.Contains(':') == true)
             {
                 // IPv6
                 host = '[' + host + ']';
@@ -266,11 +270,8 @@ private static void ProcessHostHeader(HttpRequestMessage request)
 
     private ProxyMode DetermineProxyModeAndAddressLine(HttpRequestMessage request)
     {
-        string scheme = request.GetSchemeProperty();
-        string host = request.GetHostProperty();
-        int? port = request.GetPortProperty();
-        string pathAndQuery = request.GetPathAndQueryProperty();
-        string addressLine = request.GetAddressLineProperty();
+        string? pathAndQuery = request.GetPathAndQueryProperty();
+        string? addressLine = request.GetAddressLineProperty();
 
         if (string.IsNullOrEmpty(addressLine))
         {
@@ -279,7 +280,7 @@ private ProxyMode DetermineProxyModeAndAddressLine(HttpRequestMessage request)
 
         try
         {
-            if (!UseProxy || Proxy == null || Proxy.IsBypassed(request.RequestUri))
+            if (!UseProxy || Proxy == null || Proxy.IsBypassed(request.RequestUri!))
             {
                 return ProxyMode.None;
             }
@@ -289,7 +290,7 @@ private ProxyMode DetermineProxyModeAndAddressLine(HttpRequestMessage request)
             return ProxyMode.None;
         }
 
-        var proxyUri = Proxy.GetProxy(request.RequestUri);
+        var proxyUri = Proxy.GetProxy(request.RequestUri!);
         if (proxyUri == null)
         {
             return ProxyMode.None;
@@ -299,7 +300,11 @@ private ProxyMode DetermineProxyModeAndAddressLine(HttpRequestMessage request)
         {
             if (string.IsNullOrEmpty(addressLine))
             {
-                addressLine = scheme + "://" + host + ":" + port.Value + pathAndQuery;
+                string? scheme = request.GetSchemeProperty();
+                string? host = request.GetHostProperty();
+                int port = request.GetPortProperty()!.Value;
+
+                addressLine = scheme + "://" + host + ":" + port.ToString(CultureInfo.InvariantCulture) + pathAndQuery;
                 request.SetAddressLineProperty(addressLine);
             }
             request.SetConnectionHostProperty(proxyUri.DnsSafeHost);
@@ -357,7 +362,7 @@ private async Task TunnelThroughProxyAsync(HttpRequestMessage request, Stream tr
         connectRequest.Headers.ProxyAuthorization = request.Headers.ProxyAuthorization;
         connectRequest.Method = new HttpMethod("CONNECT");
         // TODO: IPv6 hosts
-        string authority = request.GetHostProperty() + ":" + request.GetPortProperty().Value;
+        string authority = request.GetHostProperty() + ":" + request.GetPortProperty()!.Value;
         connectRequest.SetAddressLineProperty(authority);
         connectRequest.Headers.Host = authority;
 
diff --git a/src/Microsoft.Net.Http.Client/RequestExtensions.cs b/src/Microsoft.Net.Http.Client/RequestExtensions.cs
index 4c998bc3..c7872e17 100644
--- a/src/Microsoft.Net.Http.Client/RequestExtensions.cs
+++ b/src/Microsoft.Net.Http.Client/RequestExtensions.cs
@@ -12,22 +12,22 @@ public static bool IsHttps(this HttpRequestMessage request)
         return string.Equals("https", request.GetSchemeProperty(), StringComparison.OrdinalIgnoreCase);
     }
 
-    public static string GetSchemeProperty(this HttpRequestMessage request)
+    public static string? GetSchemeProperty(this HttpRequestMessage request)
     {
         return request.GetProperty<string>("url.Scheme");
     }
 
-    public static void SetSchemeProperty(this HttpRequestMessage request, string scheme)
+    public static void SetSchemeProperty(this HttpRequestMessage request, string? scheme)
     {
         request.SetProperty("url.Scheme", scheme);
     }
 
-    public static string GetHostProperty(this HttpRequestMessage request)
+    public static string? GetHostProperty(this HttpRequestMessage request)
     {
         return request.GetProperty<string>("url.Host");
     }
 
-    public static void SetHostProperty(this HttpRequestMessage request, string host)
+    public static void SetHostProperty(this HttpRequestMessage request, string? host)
     {
         request.SetProperty("url.Host", host);
     }
@@ -42,12 +42,12 @@ public static void SetPortProperty(this HttpRequestMessage request, int? port)
         request.SetProperty("url.Port", port);
     }
 
-    public static string GetConnectionHostProperty(this HttpRequestMessage request)
+    public static string? GetConnectionHostProperty(this HttpRequestMessage request)
     {
         return request.GetProperty<string>("url.ConnectionHost");
     }
 
-    public static void SetConnectionHostProperty(this HttpRequestMessage request, string host)
+    public static void SetConnectionHostProperty(this HttpRequestMessage request, string? host)
     {
         request.SetProperty("url.ConnectionHost", host);
     }
@@ -62,27 +62,27 @@ public static void SetConnectionPortProperty(this HttpRequestMessage request, in
         request.SetProperty("url.ConnectionPort", port);
     }
 
-    public static string GetPathAndQueryProperty(this HttpRequestMessage request)
+    public static string? GetPathAndQueryProperty(this HttpRequestMessage request)
     {
         return request.GetProperty<string>("url.PathAndQuery");
     }
 
-    public static void SetPathAndQueryProperty(this HttpRequestMessage request, string pathAndQuery)
+    public static void SetPathAndQueryProperty(this HttpRequestMessage request, string? pathAndQuery)
     {
         request.SetProperty("url.PathAndQuery", pathAndQuery);
     }
 
-    public static string GetAddressLineProperty(this HttpRequestMessage request)
+    public static string? GetAddressLineProperty(this HttpRequestMessage request)
     {
         return request.GetProperty<string>("url.AddressLine");
     }
 
-    public static void SetAddressLineProperty(this HttpRequestMessage request, string addressLine)
+    public static void SetAddressLineProperty(this HttpRequestMessage request, string? addressLine)
     {
         request.SetProperty("url.AddressLine", addressLine);
     }
 
-    public static T GetProperty<T>(this HttpRequestMessage request, string key)
+    public static T? GetProperty<T>(this HttpRequestMessage request, string key)
     {
 #if NET6_0_OR_GREATER
         return request.Options.TryGetValue(new HttpRequestOptionsKey<T>(key), out var obj) ? obj : default;