Diagnostics Combination

This feature will be used in parallel request hedging to combine the diagnostics of all parallel requests made.

Design

To merge diagnostics together we will add a constructor for CosmosTraceDiagnostics that takes in a list of CosmosTraceDiagnostics and merges them into one. This feature will be used for when parallel request hedging is added to the SDK as a way to have the full context for a request that sends out multiple parallel requests.

The Merged Diagnostics will be broken down into the following:

• A summary of all the requests made + status codes (this exists in the normal diagnostics)
• A name that will make it clear that this is a multi-request trace + a GUID that wraps all requests
• Start Time
• Duration for all requests
• Data
  • Client configuration
  • Total request charge
• Children containing full diagnostics strings minus client configuration for each request

Other things that can be added to data

• All regions contacted
• Multi Request Trace Reason (Parallel Request Hedging for example)