Be careful of using grpc::ClientStreamingInterface::Finish() function

No matter server-side streaming RPC or bidirectional streaming RPC, if there is still message for Client to read, but Client callsgrpc::ClientStreamingInterface::Finish(), it will block here forever. The call stack is like this:

#0  0x00007ffff5b24076 in epoll_pwait () from /usr/lib/libc.so.6
#1  0x00007ffff71c6ae5 in ?? () from /usr/lib/libgrpc.so.4
#2  0x00007ffff71e3a26 in ?? () from /usr/lib/libgrpc.so.4
#3  0x000055555558300f in grpc::CompletionQueue::Pluck (this=0x555555fd5340, tag=0x7fffffffd800)
    at /usr/include/grpc++/impl/codegen/completion_queue.h:224
#4  0x0000555555585e46 in grpc::ClientReaderWriter<..., ...>::Finish (
    this=0x555555fd5320) at /usr/include/grpc++/impl/codegen/sync_stream.h:494

So please pay attention to it. Before calling grpc::ClientStreamingInterface::Finish(), make sure the grpc::ReaderInterface::Read() return false:

while (stream->Read(&server_note)) {
  ...
}
Status status = stream->Finish();

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