pub unsafe extern "C" fn grpcwrap_call_start_server_streaming(
    call: *mut grpc_call,
    ctx: *mut grpcwrap_batch_context,
    send_buffer: *mut grpc_slice,
    write_flags: u32,
    initial_metadata: *mut grpc_metadata_array,
    initial_metadata_flags: u32,
    tag: *mut c_void
) -> grpc_call_error