feat(blocksync): sort peers by download rate & multiple requests for …

…closer blocks (cometbft#2475)

It can be reviewed commit by commit.

1. Request the block N from peer B immediately after getting
`NoBlockResponse` from peer A
cometbft@a718fb4
2. Sort peers by download rate (the fastest peer is picked first)
cometbft@cf19851
3. Request a block from peer B if we are approaching pool's height (less
than 50 blocks) and the current peer A is slow in sending us the block
cometbft@e06ebfe
cometbft@e97007f

Closes cometbft#2379 

### Benchmarks

Osmosis:

without this PR (baseline): 11.45m
with this PR: 7.29m
~ 36% decrease

---

#### PR checklist

- [x] Tests written/updated
- [x] Changelog entry added in `.changelog` (we use
[unclog](https://github.com/informalsystems/unclog) to manage our
changelog)
- [x] Updated relevant documentation (`docs/` or `spec/`) and code
comments
- [x] Title follows the [Conventional
Commits](https://www.conventionalcommits.org/en/v1.0.0/) spec

.changelog/unreleased/improvements/2475-blocksync-2nd-request.md

@@ -0,0 +1,3 @@
+- `[blocksync]` Request a block from peer B if we are approaching pool's height
+  (less than 50 blocks) and the current peer A is slow in sending us the
+  block [\#2475](https://github.com/cometbft/cometbft/pull/2475)

.changelog/unreleased/improvements/2475-blocksync-no-block-response.md

@@ -0,0 +1,3 @@
+- `[blocksync]` Request the block N from peer B immediately after getting
+  `NoBlockResponse` from peer A
+  [\#2475](https://github.com/cometbft/cometbft/pull/2475)

.changelog/unreleased/improvements/2475-blocksync-sort-peers.md

@@ -0,0 +1,2 @@
+- `[blocksync]` Sort peers by download rate (the fastest peer is picked first)
+  [\#2475](https://github.com/cometbft/cometbft/pull/2475)