Function gio_sys::g_output_stream_writev

pub unsafe extern "C" fn g_output_stream_writev(
    stream: *mut GOutputStream, 
    vectors: *const GOutputVector, 
    n_vectors: size_t, 
    bytes_written: *mut size_t, 
    cancellable: *mut GCancellable, 
    error: *mut *mut GError
) -> gboolean

This is supported on crate feature v2_60 only.