`send` functions should take a reference of message `&M` about lunatic-rs

[tqwewe]

Hmm I see, I think it might be worth looking into, since giving a reference when sending messages would strip out a bunch of cloning I would imagine. I'm not sure which resources might not be Clone. TcpListener doesn't seem to even be Serializable.
I like the solution of cloning within the serialization implementation, since most resources are just integer identifiers.

[bkolobara]

Resources make this a bit more complicated.

The reason why we don't take a reference is that some resources are moved out of the process into the message during serialization. This makes it unsafe to serialize them two times. I admit that this is not the most elegant way of coupling things, but I couldn't come up with a better solution.

We could solve this for example by just cloning resources during serialization and move the cloned ones into the message. This however would require all resources to be Clone. I'm not sure if this is true for all resources (e.g. listening socket) that can be sent between processes.