initialize the store lazily

[marten-seemann]

No description provided.

[willscott]

This means the first request will block instead of at process startup, right?

[MarcoPolo]

Worst case, yes. But you can still call Store.Init() in your own startup code if you want to pre-warm this.

This came about because we noticed dynamic allocations during our tests due to this library doing dynamic allocations in the background. And we couldn't really control it. It let to some surprising behavior to say the least. See libp2p/go-libp2p#2142

[marten-seemann]

The only place in libp2p where we used this is when checking relay reservation constraints. It should therefore be sufficient to initialize when starting the relay: https://github.com/libp2p/go-libp2p/pull/2143/files#diff-ed9fde63e4a5b43b6256b213dc16a0c0cb662c4e5471327c795bfe7867234f87