You probably don't want to use this function on resizable streams.
See Memory.outputStreamGetDataSize instead. For resizable
streams the size returned by this function is an implementation
detail and may be change at any time in response to operations on the
stream.
If the stream is fixed-sized (ie: no realloc was passed to
Memory.outputStreamNew) then this is the maximum size of the
stream and further writes will return G_IO_ERROR_NO_SPACE.
Gets the size of the currently allocated data area (available from Memory.outputStreamGetData).
You probably don't want to use this function on resizable streams. See Memory.outputStreamGetDataSize instead. For resizable streams the size returned by this function is an implementation detail and may be change at any time in response to operations on the stream.
If the stream is fixed-sized (ie: no realloc was passed to Memory.outputStreamNew) then this is the maximum size of the stream and further writes will return G_IO_ERROR_NO_SPACE.
In any case, if you want the number of bytes currently written to the stream, use Memory.outputStreamGetDataSize.