Bell Le

## What changes are proposed in this pull request? Fixes https://github.com/scalapb/protoc-bridge/issues/379 by switching from TCP sockets to Unix domain sockets with server-side read timeout on macOS. It turns out extremely...

It's found that if we use domain sockets to get around a [port conflict issue](https://github.com/scalapb/protoc-bridge/pull/381), the communication is still not very reliable on macOS. With short messages, it gets stuck...

It's found that the `nc` based communication introduced in https://github.com/scalapb/protoc-bridge/pull/367, while more reliable than the named-pipe based communication, can still get stuck or have mismatched messages occasionally during 100k runs....

https://github.com/scalapb/protoc-bridge/pull/367 switched the plugin communication to TCP sockets on macOS. Unfortunately, it's later found that sockets aren't reliable either out-of-the-box on macOS. ### TCP sockets Details: https://github.com/scalapb/protoc-bridge/pull/381 - The allocated...

## What changes are proposed in this pull request? [We are observing that the named pipe based communication in PosixPluginFrontend can get stuck on macOS with Named pipes on macOS...