Consider changing identify cache default to be non-zero

[thomaseizinger]

Description

The rust-libp2p identify implementation has a cache that remembers the reported addresses from the last X connected peers even once they get disconnected. By default, X is zero.

Motivation

Most users probably don't know about this cache and thus, do not benefit from it. If we make the default value 100, the maximum memory footprint will still be < 500kb (1 identify message has max 4096 bytes, that * 100 is still only 400kb and there is more than just addresses in the message).

Current Implementation

Are you planning to do it yourself in a pull request?

Maybe.