getMessage
Gets the #GDBusMessage for the method invocation. This is useful if you need to use low-level protocol features, such as UNIX file descriptor passing, that cannot be properly expressed in the #GVariant API.
See this gdbus-server and gdbus-unix-fd-client for an example of how to use this low-level API to send and receive UNIX file descriptors.
Return
#GDBusMessage. Do not free, it is owned by @invocation.
Since
2.26