code: function ws_send(socket, data) {
  	//console.log("send: " + data);
  	let header;
  	let payload = new Buffer.from(data);
  	const len = payload.length;
  	
  	if (len <= 125) {
  		header = new Buffer.alloc(2);
  		header[1] = len;
  	} else if (len <= 0xffff) {
  		header = new Buffer.alloc(4);
  		header[1] = 126;
  		header[2] = (len >> 8) & 0xff;
  		header[3] = len & 0xff;
  	} else { /* 0xffff < len <= 2^63 */
  		header = new Buffer(10);
  		header[1] = 127;
  		header[2] = (len >> 56) & 0xff;
  		header[3] = (len >> 48) & 0xff;
  		header[4] = (len >> 40) & 0xff;
  		header[5] = (len >> 32) & 0xff;
  		header[6] = (len >> 24) & 0xff;
  		header[7] = (len >> 16) & 0xff;
  		header[8] = (len >> 8) & 0xff;
  		header[9] = len & 0xff;
  	}
  	
  	header[0] = 0x81;
  	socket.write(Buffer.concat([header, payload],
  		 header.length + payload.length), 'binary');
  	//console.log('sent ' + data.length + ' bytes');
  }
docs: send string data to web socket