Commands/jfr

Starts and stops profiling with Java FlightRecorder as well as a few custom events.
==Usage==
Profiling contains several custom events below:
* minecraft.ServerTickTime: sampling event exposing average server tick times at one second intervals.
* minecraft.ChunkGeneration: time taken to generate individual chunk stages.
* minecraft.PacketRead | minecraft.PacketSent：network traffic.
* minecraft.WorldLoadFinishedEvent: initial world loading duration.
A summary JSON report is written both to the log file and in the debug folder accompanied by a .jfr recording ready to be analyzed in i.e JMC or any other profiler tool supporting the format.
== Syntax ==
:jfr start
:: Start JFR profiling.
:jfr stop
:: Stop JFR profiling.
== Result ==
== Output ==
== History ==
es:Comandos/jfr
ja:コマンド/jfr
pt:Comandos/jfr
zh:命令/jfr