Invoke the default getrange function of the proxy pad.
a src #GstPad, returns #GST_FLOW_ERROR if not.
the parent of @pad
The start offset of the buffer
The length of the buffer
a pointer to hold the #GstBuffer, returns #GST_FLOW_ERROR if %NULL.
a #GstFlowReturn from the pad.
See Implementation
Invoke the default getrange function of the proxy pad.