Metrics lib for the application

[thangchung]

OpenCensus should be considered https://github.com/census-instrumentation/opencensus-csharp
The sample can be found at https://www.olivercoding.com/2018-07-22-prometheus-dotnetcore/

[thangchung]

Implement OpenTracing for dotnet-core follows standard code at https://github.com/grpc-ecosystem/grpc-opentracing/blob/master/java.

Sample for dotnet-core

• https://github.com/opentracing-contrib/csharp-grpc
• https://github.com/yurishkuro/opentracing-tutorial/blob/master/csharp
• https://github.com/opentracing-contrib/csharp-netcore