Tracing parity with Durable Task Framework (DTFx)

[philliphoff]

The Durable Task Framework (DTFx) SDK provides Durable Task specific tracing across orchestration execution. The Durable Task .NET SDK provides no tracing (i.e. separate from any provided when used with Azure Durable Functions).

The Durable Task .NET SDK should match DTFx tracing so that, when used on its own, clients can get a complete picture of orchestration execution including how their own traces dovetail with DT execution.

Work in progress is here, basically a port of the DTFx behavior:

https://github.com/philliphoff/durabletask-dotnet/tree/philliphoff-orchestration-tracing

Requires some changes to the DT protos