pubsub: stop creating negative timeouts

[smcgivern]

I didn't create an issue because it had so many required steps for a one-line fix, and those steps weren't applicable in this case.

This code assumes that latency is less than 90% of the deadline, but in our production environment we see that's not always the case. When it isn't, this library tries to create a timeout with negative duration, which throws a node TimeoutNegativeWarning.

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Fixes #<issue_number_goes_here> 🦕

[gemini-code-assist]

Code Review

This pull request updates the lease manager to prevent negative timeouts by ensuring the calculated deadline extension is at least 0. The reviewer suggests enforcing a minimum delay of 1000ms instead of 0 to prevent a potential storm of rapid, back-to-back lease extension requests when latency is high.

[gemini-code-assist]

While using Math.max(0, ...) prevents negative timeouts and the resulting Node.js warnings, returning 0 when latency exceeds 90% of the deadline can lead to immediate rescheduling of lease extensions. Under high latency or network congestion, this can cause a storm of rapid, back-to-back modAck requests, further exacerbating the latency issue.

Consider enforcing a reasonable minimum delay (e.g., 1000ms) to prevent spamming the server when latency is high.

Suggested change

	return Math.max(0, deadline * 0.9 - latency) * jitter;
	return Math.max(1000, deadline * 0.9 - latency) * jitter;

[smcgivern]

Currently it's negative, so 🤷