Array and String bulk write

[yanxke]

Pull Request Details

Provide details about your pull request and what it adds, fixes, or changes.

Use the underlying io.write(buf, len) methods when there are multiple items to be written. This dramatically speeds up the transfer speeds.

Breaking Changes

Describe what features are broken by this pull request and why, if any.

None

Issues Fixed

Enter the issue numbers resolved by this pull request below, if any.

None

Other Relevant Information

Provide any other important details below.

Tested on my Adafruit M0 and it's about 3X the transfer speed over the USB serial console.

[jfjlaros]

I do not think this will work when the array contains non-POD types, e.g., an array of vectors.

[yanxke]

There should be a new method for sending buffer arrays then. The methods for sending generic types are too slow.

[jfjlaros]

I do not think overloading something like Array<uint8_t, n> will be safe. Adding an additional data member to Array will break the proposed approach for example.

Maybe an overload for specific array references could work, e.g.,

template <size_t n, size_t m>
void rpcWrite(Stream& io, uint8_t (& data)[n][m]) {
  // ...
}

[suahelen]

I had the same experience. The issue would be resolved with this PR:
jfjlaros/arduino-simple-rpc#26