Is is possible to send TCPClient print or println characters at once not sending one by one. Problem is that if Spark sending large amount of POST data to target server, then it takes a several seconds to complete POST request. Sometimes connection is interrupted and some of data is missing of end of POST request. So are there any possibilities to send POST data to server without sending bytes one by one.
String testString("This is what I want to send");
TCPClient.write( (uint8_t*)testString.c_str(), testString.length() );
TCPClient.println(); //may be needed
Don’t forget that if you had println() before you need to add a CR or LF or both to the end of your String, or just call println() like I did above.