In my testing, TCP socket maximum throughput was 12Mbps~15Mbps. you can see the testing codes from here ->
http://www.esp32.com/viewtopic.php?f=13&t=839.
UDP socket maximum throughput was 35~40Mbps between two ESP32 module(The same as above link testing configuration).
However, ESP32's specification says UDB 135Mbps.
Now I'm finding how can achieve that.