[Environment] little Runner refactorings

[mackwic]

• Extract rayon initialization
• Rename inner collections of functions
• Remove useless _with variants in the Runner

[mackwic]

This will be merged in PR #30 when approved

[regexident]

Looking good.

I just realized that fn run_with(…) does in fact not make any sense. It used to, when Configuration was still passed to it instead of fn new(…). Mea culpa. 😇

[regexident]

We might want to only call rayon::initialize(…) if threads is 1, if it is we might want to check for the function's result and log an error message if appropriate?

/// If you do not call this function, the thread pool
/// will be automatically initialized with the default
/// configuration.

/// Initialization of the global thread pool happens exactly
/// once. Once started, the configuration cannot be
/// changed. Therefore, if you call `initialize` a second time, it
/// will return an error. An `Ok` result indicates that this
/// is the first initialization of the thread pool.

(Source)

[regexident]

Reasoning being that more than a single runner can be created via rspec, each calling into rayon::initialize(…). 🤔

[mackwic]

Frankly, I didn't touched it because I don't want to break anything, but I'd much rather don't call rayon at all when parallelism is disabled.

[regexident]

By moving the block within par_iter() into a dedicated method we should be able to simply use an if self.configuration.parallel { … } else { … }. 🤔

[regexident]

Commit c324419 removes the need for rayon::initialize(…). 💪