handleUnary - startBatch callback is called with null result.read

[yoni-veksler]

Problem description

start batch callback gets called with an empty result object.

call.startBatch(batch, function(err, result) {
...
// sometimes
// result = {read: null}
try {
     // throws
      emitter.request = handler.deserialize(result.read);
    } catch (e) {
     ...
    }
})

Reproduction steps

Send huge amount of request in a short time with a small timeout. In my case sending 500 requests with 50ms timeout through 1 connection using unary streaming from go app.

Environment

• OS name, version and architecture: macOS, linux
• Node version - 8,10,12,14,6
• Node installation method - nvm, docker
• Package name and version "grpc": "1.24.11"

why is this happening ? if i debug with the GRPC_TRACE=all env var, I see huge number of requests with "grpc_message":"Received RST_STREAM with error code 8", but only few requests are throwing because of the result.read = null. So I wonder why and what is causing that.