user_timing_2 library Null safety

User Timing Level 3

https://w3c.github.io/user-timing/

Classes

PerformanceMark
PerformanceMark is an abstract interface for PerformanceEntry objects with an entryType of "mark". Entries of this type are created by calling performance.mark() to add a named DOMHighResTimeStamp (the mark) to the browser's performance timeline. [...]
PerformanceMarkOptions
PerformanceMeasure
PerformanceMeasure is an abstract interface for PerformanceEntry objects with an entryType of "measure". Entries of this type are created by calling performance.measure() to add a named DOMHighResTimeStamp (the measure) between two marks to the browser's performance timeline. [...]
PerformanceMeasureOptions