Required Plugins

[Sky9x]

Servers want to be able to require clients to install specific versions of specific plugins.

The server's list of plugins is provided in the query payload, and each entry has a required: bool.
Clients must then install every plugin that is required, with a version matching a semver tilde spec (major and minor must be equal, patch is ignored). This way, plugins can have breaking codec changes in minor versions.

However, as a silly preventative measure for the plugin set changing in the time between the query and the client connecting (that maybe could be postponed), the server sends a hash of the required plugin set in the query payload, and the client then sends it back while connecting to a session. If they don't match, the client disconnects with an error, to avoid weird bugs due to mismatched plugin versions (this also happens with PVNs).

Unresolved:

• Do we need a hash? (in this PV? postpone?)
• Could we just send the entire plugin set json instead? (hash is supposed to avoid this cuz plugin sets may get large)
• How is the hash calculated?
• Can clients calculate their own hashes (or is hash calculation server impl specific)?
• How big is the hash? (32 bytes?)