A PHP internals mailing list thread discussing a proposed RFC to introduce a new `Time\Duration` class in PHP 8.6. The class is designed to represent stopwatch-style durations (not calendar periods) to improve developer experience for timeout APIs, particularly the new Polling API. The RFC intentionally keeps the API minimal, using a seconds+nanoseconds internal representation similar to Rust's and Java's Duration. Discussion covers design decisions including: why the highest constructor unit is hours, omission of ISO 8601 serialization and floating-point methods for now, namespace choice (`Time` vs `DateTime`), whether to use `add`/`sub` vs a variadic `sum` method, and why the JavaScript Temporal API's `temporal_rs` library was not adopted as a dependency.
