[FEATURE REQ] EventHub distributed tracing: stamp EventHubs info on message spans

[lmolkova]

Is your feature request related to a problem? Please describe.
Currently message spans do not have any information about event hub they are being sent to.
It could be discovered by following to the linked 'send' span which has attributes describing EventHubs and entity. So it is not a problem for human beings debugging single trace, but creates a a problem for analysis and visualization tools (such as Azure Monitor).
It is inefficient and hard to build aggregated views such as application map and analyze things like number of messages per send call without information about EventHubs on message.

Describe the solution you'd like
stamp event hub properties on message spans:

• message_bus.destination: EventHubs entity name
• peer.address: Fully qualified EventHubs name such as <name>.servicebus.windows.net/

Describe alternatives you've considered
Discover relationships between message and and send span on monitoring tool backend to build aggregated views and metrics. It appears to be expensive (from querying perspective) and contributes to bad performance showing up such views.

Additional context

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[joshfree]

@samvaity could you please pick this up for the next monthly update?

[joshfree]

Moving this tracing item to the April release as well