Callable
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						Gets the Performanceservice.firebase.performance()can be called with no arguments to access the default app'sPerformanceservice. ThePerformanceservice does not work with any other app.The Performance SDK does not work in a Node.js environment. Parameters- 
								Optional app: AppThe app to create a performance service for. Performance Monitoring only works with the default app. If not passed, uses the default app. 
 Returns Performance
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The Performance SDK does not work in a Node.js environment.