Starts an asynchronous load of the @file's contents.
For more details, see g_file_load_contents() which is
the synchronous version of this call.
When the load operation has completed, @callback will be called
with @user data. To finish the operation, call
g_file_load_contents_finish() with the #GAsyncResult returned by
the @callback.
If @cancellable is not %NULL, then the operation can be cancelled by
triggering the cancellable object from another thread. If the operation
was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
Starts an asynchronous load of the @file's contents.
For more details, see g_file_load_contents() which is the synchronous version of this call.
When the load operation has completed, @callback will be called with @user data. To finish the operation, call g_file_load_contents_finish() with the #GAsyncResult returned by the @callback.
If @cancellable is not %NULL, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.