Support notify first shred received in geyser

[lijunwangs]

Problem

This is the first part to support more slot status notification type in geyser. FirstShredReceived.

Summary of Changes

Link SlotStatusNotifier in retransmit stage on FirstShredReceived.

Tests: tested change with Postgres geyser plugin and confirming the FirstShredReceived being received.

Fixes #

#2957

[fanatid]

Thank you! Is it also possible to add Completed, CreatedBank, Dead?

[lijunwangs]

Thank you! Is it also possible to add Completed, CreatedBank, Dead?

Yes. Will be done in follow-on PRs to cut down one PR size.

[bw-solana]

Overall LGTM. Left a few comments

[bw-solana]

Are the comments for the other SlotStatus enums wrong? Almost seems like they were copy pasted from confirmation levels.. We send theses notifications out each time a slot transitions to the new state, right (assuming it makes it to that state)?

[lijunwangs]

Yes -- they were largely copied. Which one is wrong?

[bw-solana]

I think the part explaining this is "The highest slot" makes more sense in the context of confirmation levels.

I would probably rewrite them like this:

    /// First shred has been received for this slot.
    FirstShredReceived,

    /// This slot has been processed.
    Processed,

    /// This slot has been optimistically confirmed by a supermajority of the cluster.
    Confirmed,

    /// This slot has been confirmed and reached max vote lockout on the canonical fork.
    Rooted,

I acknowledge this is sort of out of scope for this PR - I just noticed it because your comment is written more like how I would expect for a slot status notification but doesn't quite match the others.

[bw-solana]

LGTM

Is the plan to build out more of the supporting functions in a follow-up PR? I'm thinking things like these:
https://github.com/anza-xyz/agave/blob/master/geyser-plugin-manager/src/slot_status_notifier.rs#L28-L40
https://github.com/anza-xyz/agave/blob/master/geyser-plugin-interface/src/geyser_plugin_interface.rs#L324-L332