gRPC support

Changes

• Support gRpc

collector.conf

       [Collector]
        # collectorhost and specific port
        AgentID=your_id
        ApplicationName=your_name
        collector.grpc.agent.ip=collectorHost
        collector.grpc.agent.port=9991
        collector.grpc.stat.ip=collectorHost
        collector.grpc.stat.port=9992
        collector.grpc.span.ip=collectorHost
        collector.grpc.span.port=9993

Know Issues

https://github.com/naver/pinpoint-c-agent/issues?utf8=%E2%9C%93&q=is%3Aissue+label%3A%22Known+problem%22

Thanks

#157