## Why
The command execution ID is a UUID that should be initialized once, and
then have a consistent read value for the duration of the command.
As we start emitting telemetry events, we also want to emit the command
execution ID in the telemetry payload. This library helps consolidate
all reads to the `cmd-exec-id` value, and ensures there's only one write
for the UUID.
relevant comment:
https://github.com/databricks/cli/pull/2432#discussion_r1982884235
## Tests
Unit tests.
## Changes
This PR adds the `cmd-exec-id` field to the user agent. This allows us
to correlate multiple HTTP requests made from the CLI.
### Why Not Use HTTP traceparent?
We considered using the traceparent header in HTTP as an alternative,
but it's not a good fit for our use case. Here's why:
1. Purpose of traceparent: It's designed to trace a single HTTP request
across a distributed system as it moves through subsystems and proxies.
2. Our requirement: We need to trace multiple HTTP requests made during
a single command execution in the CLI.
For more details about how traceparent itself works and how it's used in
the Go SDK, see
https://github.com/databricks/databricks-sdk-go/pull/914.
## Tests
Unit test
shreyas-goenka