Would be better if both GstAppSrc and GstAppSink operate on GstSample. 

Use case: If a pipeline bridge is created between appsink of a pipeline to appsrc of another pipeline then, always buffer copy has to be made before pushing the buffer to GstAppSrc, because there is no API on appsrc which can accept GstSample of GstSample of the GstAppSink (gst_app_sink_pull_sample API).

There is an overhead of gst_buffer_copy of every buffer in the following code (Present API)
  GstSample *sample = gst_app_sink_pull_sample(appsink);
  gst_app_src_push_buffer(appsrc,
     gst_buffer_copy(gst_sample_get_buffer(sample)));
  gst_sample_unref(sample);
  // push_buffer api takes owner ship of the GstBuffer, so we can't just pass the buffer of the sample instead we have to copy the buffer and push to appsrc

With the proposed API for GstAppSrc (gst_app_src_push_sample())

  GstSample *sample = gst_app_sink_pull_sample(appsink);
  gst_app_src_push_sample(appsrc, sample); // which will take owner ship of the sample