Add geyser block-metadata notification with entry count

[CriesofCarrots]

Problem

Geyser stream consumers don't know how many entries to expect.

Summary of Changes

Include entry count in block-metadata notification

Fixes #32988

[codecov]

Codecov Report

Merging #33359 (8a62aaa) into master (3e8ccbe) will increase coverage by 0.0%.
Report is 1 commits behind head on master.
The diff coverage is 0.0%.

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##           master   #33359   +/-   ##
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  Coverage    81.9%    81.9%           
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  Files         796      796           
  Lines      215842   215853   +11     
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+ Hits       176910   176921   +11     
  Misses      38932    38932           

[lijunwangs]

Looks good to me on geyser side change. I will defer to @carllin on the entry_count is real entry_count in the block.

[CriesofCarrots]

I will defer to @carllin on the entry_count is real entry_count in the block.

Exactly the bit I was hoping @carllin would review :) Carl, please sanity check; I think we concluded that this would be a legit way to use progress_map.

[carllin]

Looks right! Confirming this is necessary in addition to the existing entry notifications here (which includes the entry index)?

solana/ledger/src/blockstore_processor.rs

Lines 1148 to 1159 in b5c466d

	if let Some(entry_notification_sender) = entry_notification_sender {
	let entry_index = progress.num_entries.saturating_add(i);
	if let Err(err) = entry_notification_sender.send(EntryNotification {
	slot,
	index: entry_index,
	entry: entry.into(),
	}) {
	warn!(
	"Slot {}, entry {} entry_notification_sender send failed: {:?}",
	slot, entry_index, err
	);
	}

. The client can't conclude when the block is over by the latest entry notification?

[CriesofCarrots]

The client can't conclude when the block is over by the latest entry notification?

Correct, there's no way for a client to know which entry notification is the expected last one. Technically, there currently exists a way to determine this by tracking all transactions and using the executed_transaction_count to find the last transaction and look at its entry index, but this forces clients to follow all transactions, even if they are only interested in entry notifications.