Support Network Diagnostics/Event Streaming

[jbristowe]

Currently, network activity (i.e. diagnostics, I/O event streaming) is not supported by CLI through an environment variable, flag, etc.

The ability to see network activity streamed to stdout could help customers who are experiencing connectivity problems with the CLI -- especially if they do not have appropriate tools installed to diagnose the problem (i.e. trace proxy). The CLI could expose a flag that -- when enabled -- would stream network-related events (i.e. HTTP request/response) to stdout.