a GSocketAddress, or NULL. [allow-none]
the buffer containing the data to send. [array length=size][element-type guint8]
the number of bytes to send
a GCancellable or NULL. [allow-none]
Number of bytes written (which may be less than size), or -1 on error
GException on failure.
Tries to send size bytes from buffer to address. If address is NULL then the message is sent to the default receiver (set by g_socket_connect()). See g_socket_send() for additional information. Since 2.22