code: public static <M, A extends InetSocketAddress> AddressedEnvelope<M, A> of(M message, A sender) {
          return new DefaultAddressedEnvelope<>(message, null, sender);
      }
docs: Returns a {@link AddressedEnvelope} of the given message and message sender values.
  
  @param message the message
  @param sender the sender address
  @param <M> message type
  @param <A> sender type
  @return the envelope