feat: Lazy iter

[JonathanWoollett-Light]

Summary of the PR

wait now returns an iterator that allows lazily evaluating event closures. This allows for returning an error when the 1st closure returns an error, rather than always needing to evaluate every closure.

Benchmarks

process_basic           time:   [9.8147 µs 9.8172 µs 9.8200 µs]
                        change: [-26.640% -26.587% -26.539%] (p = 0.00 < 0.05)
                        Performance has improved.
Found 14 outliers among 200 measurements (7.00%)
  1 (0.50%) low mild
  3 (1.50%) high mild
  10 (5.00%) high severe

process_with_arc_mutex  time:   [12.021 µs 12.028 µs 12.035 µs]
                        change: [-10.332% -10.228% -10.105%] (p = 0.00 < 0.05)
                        Performance has improved.
Found 14 outliers among 200 measurements (7.00%)
  8 (4.00%) high mild
  6 (3.00%) high severe

process_with_inner_mut  time:   [10.447 µs 10.453 µs 10.459 µs]
                        change: [-18.906% -18.843% -18.762%] (p = 0.00 < 0.05)
                        Performance has improved.
Found 8 outliers among 200 measurements (4.00%)
  5 (2.50%) high mild
  3 (1.50%) high severe

process_dynamic_dispatch
                        time:   [20.935 µs 20.943 µs 20.951 µs]
                        change: [+13.610% +13.720% +13.836%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 10 outliers among 200 measurements (5.00%)
  6 (3.00%) high mild
  4 (2.00%) high severe

process_dispatch_few_events
                        time:   [555.07 ns 555.70 ns 556.37 ns]
                        change: [-22.108% -22.014% -21.925%] (p = 0.00 < 0.05)
                        Performance has improved.

Requirements

Before submitting your PR, please make sure you addressed the following
requirements:

• All commits in this PR are signed (with git commit -s), and the commit
  message has max 60 characters for the summary and max 75 characters for each
  description line.
• All added/changed functionality has a corresponding unit/integration
  test.
• All added/changed public-facing functionality has entries in the "Upcoming
  Release" section of CHANGELOG.md (if no such section exists, please create one).
• Any newly added unsafe code is properly documented.