- Improve the comment and its format.
- Create a concret class type to replace Tuple and ValueTuple.
- Verify method parameter values.

- Combine the error telemetry event with the non-error one.
- Collect if the http request is canceled when we send http request.

- Refactor the telemetry and use a class for the collected data in each
  telemetry event.
- Now we only get basic information and push them to the data flow.
- A thread from thread pool handles the data, transform them, and send
  it.

- Updated the test after the refactor.
- Add more test cases.
- We don't set SuggestionSource on the suggestion in some cases. This is
  revealed in the unit tests. They're fixed.

- We have two CommandLinePredictor in AzurePredictorService. The
  CommandLinePredictor needs to extract from the user input the command
  name, parameter set etc. It's duplicate if we do that in both
  CommandLinePredictor. Move that extraction to AzurePredictorService
  and the CommandLinePredictor will not need to do it.

- Remove the string manipulation.
- Pre-allocate the collections for the result.
- Remove invariant check in "readonly" properties.