API adjustments needed

[io7m]

The current design suffers from a couple of problems:

1. Step resolution errors aren't structured errors. The API was designed before seltzer existed.
2. The way nested tasks were implemented results in a less than great appearance when the task is rendered as a tree. Specifically, every task begins with a step that has the same name as the task. These names should be given separately.

Task recorders should gain an API to set attributes on the current step, for structured errors.

[io7m]

Additionally, task recorders could/should be AutoCloseable.

Turns out they already are, but IDEA disabled the warning.

[io7m]

What bothers me is that this is now so close to the OpenTelemetry tracer API. Both APIs capture:

• Spans (Tasks/Subtasks in taskrecorder terms)
• Events (Steps in taskrecorder terms)
• Attributes (The same in both, although OpenTelemetry attributes are typed)

I wonder if the entire taskrecorder library could be a custom implementation of the Tracer API...