Chain a buffer to this.
The function returns FLUSHING if the pad was flushing.
If the buffer type is not acceptable for this (as negotiated with a preceding GST_EVENT_CAPS event), this function returns NOT_NEGOTIATED.
The function proceeds calling the chain function installed on this (see
gst_pad_set_chain_function) and the return value of that function is returned to the caller.
NOT_SUPPORTED is returned if this has
no chain function.
In all cases, success or failure, the caller loses its reference to buffer after calling this function.
| this |
a sink Pad, returns GST_FLOW_ERROR if not. |
| buffer |
the Buffer to send, return GST_FLOW_ERROR if not. |