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 Apache SkyWalking typically collect data from 
 1. Language agent, including Java, .Net, PHP, Golang, NodeJS, Lua.
 1. Service mesh proxy, especially Envoy controlled by Istio
+1. Meter data, also known pure metrics data.
 1. 3rd libs, such as Zipkin, Jaeger
 
 This repo hosts the protocol of SkyWalking native report protocol, defined in gRPC. Read [Protocol DOC](https://github.com/apache/skywalking/blob/master/docs/en/protocols/README.md#probe-protocols) for more details