ClientContext (tcp) updates (#5089)

* +sync, get/set default nodelay, sync

* default nodelay=1

* update flush()

* fix return value

* ClientContext: put things together

* ClientContext: fix debugging messages

* WiFiClient: move static members out of the class, add comments

* remove circular dependency

* parameter and return value for Client::flush&stop, flush timeout raised to 300ms

* tcp flush: restart timer on ack receive

* OTA protocol needs setNoDelay(true)

* fix Ethernet with Client changes

* 1 line unredable -> 5 lines readable code

* doc

* Update client-class.rst

* Added details for getters

libraries/ArduinoOTA/ArduinoOTA.cpp

@@ -290,6 +290,8 @@ void ArduinoOTAClass::_runUpdate() {
     }
     _state = OTA_IDLE;
   }
+  // OTA sends little packets
+  client.setNoDelay(true);
 
   uint32_t written, total = 0;
   while (!Update.isFinished() && client.connected()) {