data using the connection of the this.
If it cannot be sent immediately, it will be queued for transmission in this. The contents of
will then be serialized and transmitted when the connection of the this becomes writable. In case the
message is queued, the ID returned in
id will be non-zero and used as the ID argument in the message_sent callback.
This function will take ownership of
data and g_free it after use.
the data to queue
location for a message ID or
the size of