Allow to set TCP timeout manually

[mdivkovic]

Consider this an enhancement request. I'm using this library in communication between an ESP8285 as the WebSocket server and an Android device as the client. The devices need to communicate with each other through the WiFi hotspot of the Android device.

It turns out, for some Android devices (e.g. Samsung Galaxy S8 running Android 9), a client->tcp->write occasionally takes longer than 2 seconds, causing a partial frame being sent and an invalid header of the next frame received on the Android side, which results in Android WebSockets libraries closing the connection, in accordance with the RFC.

I've changed WEBSOCKETS_TCP_TIMEOUT to a larger value and the problem has disappeared, but it would be nice if I could set the timeout without changing the library source code.

[ramapcsx2]

Seconded.
It would be extremely helpful to define client TCP timeouts from outside the library.
In my case, I can deal with broken pipes on the website / JS, but I can't deal with the 2 second MCU stalls well.
I would want to reduce the TCP timeout, either per client or globally for all clients.

[sovcik]

solved in #501