Merge bitcoin/bitcoin#25720: p2p: Reduce bandwidth during initial headers sync when a block is found

f6a916683d75ed5489666dbfbd711f000ad0707f Add functional test for block announcements during initial headers sync (Suhas Daftuar)
05f7f31598b8bb06acb12e1e2a3ccf324b035ea8 Reduce bandwidth during initial headers sync when a block is found (Suhas Daftuar)

Pull request description:

  On startup, if our headers chain is more than a day behind current time, we'll pick one peer to sync headers with until our best headers chain is caught up (at that point, we'll try to sync headers with all peers).

  However, if an INV for a block is received before our headers chain is caught up, we'll then start to sync headers from each peer announcing the block.  This can result in doing a big headers sync with many (if not all) of our peers simultaneously, which wastes bandwidth.

  This PR would reduce that overhead by picking (at most) one new peer to try syncing headers with whenever a new block is announced, prior to our headers chain being caught up.

ACKs for top commit:
  LarryRuane:
    ACK f6a916683d75ed5489666dbfbd711f000ad0707f
  ajtowns:
    ACK f6a916683d75ed5489666dbfbd711f000ad0707f
  mzumsande:
    ACK f6a916683d75ed5489666dbfbd711f000ad0707f
  dergoegge:
    Code review ACK f6a916683d75ed5489666dbfbd711f000ad0707f
  achow101:
    ACK f6a916683d75ed5489666dbfbd711f000ad0707f

Tree-SHA512: 0662000bd68db146f55981de4adc2e2b07cbfda222b1176569d61c22055e5556752ffd648426f69687ed1cc203105515e7304c12b915d6270df8e41a4a0e1eaa

0 files changed, 0 insertions, 0 deletions