Update extending-the-sdk Readme to call out that the exporter can not make any assumptions about the Metric batch (#3071)
Update extending-the-sdk Readme to call out that the exporter can not make any assumptions about the Metric batch (#3071)


open-telemetry/opentelemetry-dotnet,open-telemetry/opentelemetry-dotnet,open-telemetry/opentelemetry-dotnet