Signed-off-by: Daniel Hu <[email protected]>

Signed-off-by: Daniel Hu <[email protected]>

- Added English and Chinese documentation for the Task Retry feature in README.md and README_zh.md respectively.
- Included an example of how to use the Task Retry feature in GoPool.
- Added a unit test for the Task Retry feature in gopool_test.go.
- The unit test checks that a task is retried the correct number of times.

Signed-off-by: Daniel Hu <[email protected]>

- Updated the task examples in README.md and README_zh.md to return a result and an error.
- This change reflects the updated task signature in GoPool.

Signed-off-by: Daniel Hu <[email protected]>

Signed-off-by: Daniel Hu <[email protected]>

Notify adjustWorkers to exit to prevent ticker resource leak

- Replace `exitChan` with `context.Context` and `context.CancelFunc` in `goPool` struct.
- Create a cancellable context in `NewGoPool` function and store the context and cancel function in `goPool` struct.
- Call the cancel function in `Release` method to notify all goroutines to exit.
- Listen to the Done channel of the context in `adjustWorkers` method to exit the goroutine when the context is cancelled.

Signed-off-by: Daniel Hu <[email protected]>

- Introduced a new GoPool interface that includes all public methods of the goPool struct.
- Updated the NewGoPool function to return the GoPool interface instead of the goPool struct.
- This change makes the GoPool interface visible outside the package and allows for future extensions with different GoPool implementations.

Signed-off-by: Daniel Hu <[email protected]>