This is better for performance because these then don't need to be reevaluated every time they are called.
When encountering an unqualified function or constant reference, PHP will first try to locate a symbol in the current namespace by that name, and then fall back to the global namespace.
This short-circuits the check, which has substantial performance effects in some cases - in particular, ord(), chr() and strlen() show ~1500x faster calls when they are fully qualified.
However, this doesn't mean that PM is getting a massive amount faster. In real world terms, this translates to about 10-15% performance improvement.
But before anyone gets excited, you should know that the CodeOptimizer in the PreProcessor repo has been applying fully-qualified symbol optimizations to Jenkins builds for years, which is one of the reasons why Jenkins builds have better performance than home-built or source installations.
We're choosing to do this for the sake of future SafePHP integration and also to be able to get rid of the buggy CodeOptimizer, so that phar and source are more consistent.
This allows other threads to notify the main thread to wake it up while it's sleeping between ticks, allowing reduction of processing latency.
Currently only RakLib and the CommandReader threads utilize this, but it's planned to extend it to more things in the near future.
CommandReader is now event-driven instead of poll-based - the server will not poll the CommandReader thread for messages each tick anymore.
RakLib utilizes this mechanism to get packets processed without delays to lower latency.
This now adds an extra dependency - `pocketmine/snooze` library contains the meat of the code used for this. See the Snooze repository for details.
this needs further changes (particularly to Furnace) to stop things abusing NBT for runtime data handling, otherwise performance is going to drop off a cliff.
