C-WCOW: Investigate message unpacking and data structures for gcs-sidecar bridge

[MahatiC]

• This would look something similar to ListenAndServe on lcow guest bridge: https://github.com/microsoft/hcsshim/blob/main/internal/guest/bridge/bridge.go#L227

• Also investigate AssignHandlers mechanism for gcs-sidecar bridge, so that there is a mapping between bridge events and function handlers. Something similar to https://github.com/microsoft/hcsshim/blob/main/internal/guest/bridge/bridge.go#L198

[MahatiC]

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