code: func (d *OneToOneEnvelope) TryNext() (*events.Envelope, bool) {
  	data, ok := d.d.TryNext()
  	if !ok {
  		return nil, ok
  	}
  
  	return (*events.Envelope)(data), true
  }
docs: // TryNext returns the next V1 envelope to be read from the diode. If the
  // diode is empty it will return a nil envelope and false for the bool.