Error R10 (Boot timeout) in web dyno startup component

Goal: Ensure that a Heroku web dyno reliably binds to the $PORT environment variable within the 60‑second boot window to prevent Error R10 (Boot timeout).

Constraint: The current platform does not expose a way to adjust the boot timeout or to receive early warnings when the dyno fails to bind $PORT, leaving developers to rely solely on the final R10 log entry.

Uncertainty: It is unclear whether extending the timeout, adding configurable health‑check hooks, or improving startup‑phase logging would be feasible without affecting existing buildpacks or third‑party integrations that assume the 60‑second limit.

Questions: What mechanisms could Heroku provide to signal a pending boot timeout before the R10 error is emitted? Would exposing a configurable boot‑timeout flag via the platform API break existing expectations for buildpacks and add‑ons? How could enhanced startup‑phase logging be introduced to help developers diagnose missing $PORT bindings earlier without altering the default behavior for existing applications?