a #GAsyncResult
a location to place the contents of the file
a location to place the current entity tag for the file, or %NULL if the entity tag is not needed
%TRUE if the load was successful. If %FALSE and @error is present, it will be set appropriately.
GException on failure.
Finishes an asynchronous partial load operation that was started with g_file_load_partial_contents_async(). The data is always zero-terminated, but this is not included in the resultant @length. The returned @contents should be freed with g_free() when no longer needed.