Function gstreamer_rtp_sys::gst_rtp_header_extension_write

pub unsafe extern "C" fn gst_rtp_header_extension_write(
    ext: *mut GstRTPHeaderExtension, 
    input_meta: *const GstBuffer, 
    write_flags: GstRTPHeaderExtensionFlags, 
    output: *mut GstBuffer, 
    data: *mut u8, 
    size: size_t
) -> size_t

This is supported on crate feature v1_20 only.