Constant INVENTORY_BUSY_PEER_WAIT_TIMEOUT 

pub const INVENTORY_BUSY_PEER_WAIT_TIMEOUT: Duration;

How long a single-hash Request::BlocksByHash waits for eligible busy capacity before returning a local refusal.

Sync and gossip downloaders use Request::BlockDownload instead: capacity waits do not consume peer attempts, and the caller bounds the complete readiness and response operation. The connection’s REQUEST_TIMEOUT starts at wire dispatch.