- Added `getCurrentTime()` as public API, providing millisecond timestamps for runtime measurements with special support for 32 bit systems. Returned timestamps are relative to an arbitrary point in time, so this API is only suitable to compare two timestamps generated in the same process.
- Fixed cancellation trace recording in `TracingDriver`
### 2.3.1
- Fixed `TracingDriver` not overriding all methods.
2.3.0
-----
- Added `TracingDriver` to debug (hanging) tests / applications. The environment variable `AMP_DEBUG_TRACE_WATCHERS=true` can be set to automatically create a `TracingDriver` wrapping the actual driver. `TracingDriver::dump()` can be used to dump all enabled, referenced watchers keeping the loop running.
- Fixed backpressure release on `Emitter::emit()`, the backpressure is now released as soon as the value is consumed, instead of the next value being requested.
2.2.0
-----
- Added `CombinedCancellationToken`
- Added `delay()` as shortcut for `new Delayed`
### 2.1.2
- Fixed issue where the loop time in `NativeDriver` was not refreshed after waiting for I/O streams (#256)
- Fixed compatibility issue of `NativeDriver` with `pcntl_async_signals()` (#264)
- A custom queue is now used for timers in `NativeDriver` to allow cancelled timers to be garbage collected immediately instead of after their original expiration time (#220)
- Resolving a promise with an object that throws when destructed will now forward that exception to the event loop error handler (#271)
- Fixed loop time to support 32-bit systems (#252, #273)
### 2.1.1
- Fixed a bug in NativeDriver causing 100% CPU usage when any timers were used (#251)
- Resolution methods are now hidden in the `Promise` returned from `Deferred::promise()`. Their exposure was an implementation detail and never promised by the return type of `Deferred::promise()`.
- A named class is now used for promises, so you don't end up with an anonymous class in `var_dump()` and stack traces, which can be confusing.
- Fixed possible notices in `formatStacktrace()`. This is an internal API, but the notices might appear on certain stack traces when running with `AMP_DEBUG=true`.
- Fixed segfault with `ev`, see amphp/parallel-functions#3.
- Dropped multiple definitions of `Deferred` and `Emitter`. These were introduced as performance hack, but relied on `zend.assertions` being disabled to change behavior, which is bad. The performance impact is believed to be rather low, because coroutines are used a lot more than `Deferred` in Amp v2.
-`Loop::set()` replaces the current driver with a dummy driver for the time of `gc_collect_cycles()` now. This allows cyclic references to be cleaned up properly before the new driver is set. Without such a fix, cyclic references might have been cleaned up later, e.g. cancelling their watcher IDs on the new loop, thereby cancelling the wrong watchers.
*`Amp\reactor()` has been replaced with `Amp\Loop::set()` and `Amp\Loop::get()`.
*`Amp\driver()` has been replaced with `Amp\Loop\Factory::create()`.
*`Amp\tick()` no longer exists and doesn't have a replacement. Ticks are an internal detail.
* Functions for creating and managing watchers are now static methods of `Amp\Loop` instead of functions in the `Amp` namespace.
*`once()` is now `delay()` and `immediately()` is `defer()`.
* Parameter order for `delay()` and `repeat()` has been changed.
*`reference()` and `unreference()` have been added.
*`Amp\Pause` has been renamed to `Amp\Delayed` and accepts an optional resolution value now. Additionally `reference()` and `unreference()` methods have been added.
* Promise accepting functions have been moved to the `Amp\Promise` namespace.
*`Amp\Promise\some()` accepts an additional `$required` parameter.
*`Amp\call()`, `Amp\asyncCall()`, `Amp\coroutine()` and `Amp\asyncCoroutine()` have been added.
*`Amp\resolve()` has been removed, use `Amp\call()` instead.
*`Promise::when()` has been renamed to `Promise::onResolve()`
*`Promise::watch()` has been removed, use `Amp\Iterator`, [`amphp/byte-stream`](https://github.com/amphp/byte-stream) or a custom implementation that implements `Amp\Promise` instead and provides dedicated APIs to access the previously data shared via the `watch()` mechanism.
*`Amp\Iterator`, `Amp\Emitter` and `Amp\Producer` have been added with several functions in the `Amp\Iterator` namespace.
