Consider relaxing NodeId: Default bound

[xDarksome]

Is your feature request related to a problem? Please describe.

We're currently integrating libp2p with openraft and having a small issue of libp2p::PeerId not implementing Default (and conceptually I don't think it should).

Describe the solution you'd like

It would be great if you could remove the bound

Describe alternatives you've considered

For now, we're going to use a newtype on top of libp2p::PeerId or some intermediary type.

Additional context

It seems that the Default is being used quite extensively across the codebase. However, I don't think it's actually necessary - Option<T> should suffice.

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[drmingdrmer]

I'm afraid removing NodeId: Default from the current codebase may not be straightforward. Types like LeaderId need to offer a zero value for uninitialized states or testing purposes. Utilizing Option would introduce unnecessary error handling using unwrap().

For your specific scenario, a potential and straightforward solution is to encapsulate libp2p::PeerId within another struct that implements Default:

struct P2PNodeId(libp2p::PeerId);
impl Default for P2PNodeId {
  fn default() -> Self { /* ... */ }
}

[xDarksome]

Yes, that's exactly how we're handing it now, it works fine, aside from some additional boilerplate of converting the types back and forth.

If there's ever going to be a refactoring/redesign of how you handle LeaderId internally, please, consider this issue.

[drmingdrmer]

Glad to hear that the workaround is functioning well for you.
If there's ever an opportunity to refactor, I will definitely keep your suggestion in mind.

Thank you for raising this issue.