Support dumping plain text network traffic

[bgrainger]

.NET 5 added a SocketsHttpHandler.PlaintextStreamFilter Property. This allows user code to inspect the plaintext HTTP protocol traffic before it's written to the network.

Per dotnet/runtime#37915 (comment), https://github.com/wfurt/PcapStream/blob/main/src/PcapStream/PcapStream.cs is a project that writes Stream data to a file in the pcap format. This allows it to be imported into Wireshark and viewed.

We could do something similar as a workaround for dotnet/runtime#37915 not (yet) being implemented:

• Add a MySqlDataSource property for a plaintext stream filter
• Recommend the use of PcapStream to log the data