Feature Request: Add tags/labels option to VStream request

[twthorn]

Feature Description

Provide an option for specifying a mapping of labels to values in a vstream request. These labels can be added to all metrics & logged messages.

Alternatively, just a single string field that a client can specify its client name in.

Use Case(s)

Vtgates accept connections from several different clients. The metrics & logs are difficult to trace back to which client initiated them. By allowing clients to self-identify themselves and logging/adding this to metrics, it makes it easier to debug issues.