get-performance.md

## getPerformance

<!-- UTSAPIJSON.getPerformance.description -->

<!-- UTSAPIJSON.getPerformance.param -->

<!-- UTSAPIJSON.getPerformance.returnValue -->

<!-- UTSAPIJSON.getPerformance.compatibility -->

<!-- UTSAPIJSON.getPerformance.tutorial -->

<!-- UTSAPIJSON.get-performance.example -->

<!-- UTSAPIJSON.general_type.name -->

<!-- UTSAPIJSON.general_type.param -->