Implement tracing for client methods, transports

[heaths]

We need to implement tracing for all client methods and transports. PII needs to be sanitized and the safest option it so remove incidental printing of values e.g., derive or implement Debug and/or Display sparingly.

For now we are using the tracing crate and friends because it supports OpenTelemetry et. al. We could consider other options but these crates are fairly ubiquitous. The opentelemetry crate and friends are geared almost entirely to OpenTelemetry and would be good to understand how that is an advantage over something more generic.

[heaths]

We need to be able to define client-level fields. I opened a tracking issue for some options using the #[tracing::instrument] procedural macro. We could accomplish "client fields" with some boilerplate and/or helper functions in every client method but that gets tedious and error-prone for convenience methods.