refactor: remove Dispatcher and related methods, closes #290

[geieredgar]

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Documentation
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change? (check one)

• Yes. Issue Remove Dispatcher and related methods #290
• No

The PR fulfills these requirements:

• When resolving a specific issue, it's referenced in the PR's title (e.g. fix: #xxx[,#xxx], where "xxx" is the issue number)
• A change file is added if any packages will require a version bump due to this PR per the instructions in the readme.

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)

Other information:
Blocked until a new version containing #289 is released.

[nothingismagick]

Awesome! Can you just run cargo +nightly format, then this should be good to go.

[geieredgar]

@nothingismagick Running cargo +nightly fmt did not change anything, so I went ahead and fixed the clippy warning manually in the last added commit. However, the warning is not at all related to my changes. I think it is triggered by a new clippy version in the CI.

[wusyong]

I believe it's because of new clippy lint. I could merge it and fix those later.