react-native-tcp-socket tcp data transfer is slow

Hi, 
I use react-native-tcp-socket to transfer large file between devices in the LAN wifi. But I found that it was slow. 
The throughput was about 1MB/s. The devices have good hardware specifications. And I'm on a gigabit LAN which has a theoretical transfer speed of 125MB/s.

Could anyone help me improve the transfermation speed. Thanks, really appreciate it!