code: func (d *Descriptor) HandleWrite(h WriteHandler) {
  	d.Property |= CharWrite | CharWriteNR
  	d.WriteHandler = h
  }
docs: // HandleWrite makes the descriptor support write and write-no-response requests, and routes write requests to h.
  // The WriteHandler does not differentiate between write and write-no-response requests; it is handled automatically.
  // HandleWrite must be called before the containing service is added to a server.