optimize some codes with global static variables

[SKTT1Ryze]

🤔 This is a ...

• New feature
• Bug fix
• Performance optimization
• Enhancement feature
• Refactoring
• Code style optimization
• Test Case
• Branch merge
• Workflow
• Other (about what?)

💡 Background and solution

Hello, everyone. I was learning the project this morning and found some code can be optimized by removing the unnecessary RwLock<T> and OnceLock<T>. In the following code, RUNTIME_CONTROLLER can be wrapped with OnceCell<T> only because it is initialized once and accessed in single thread.

// [`OnceLock<T>`] and [`RwLock<T>`] are unnecessary.
static RUNTIME_CONTROLLER: OnceLock<std::sync::RwLock<RuntimeController>> =
    OnceLock::new();

// we can use [`OnceCell<T>`] instead.
static RUNTIME_CONTROLLER: OnceCell<RuntimeController> = OnceCell::new();

What's more, &static str can be created with include_str! for more concise coding style.

Thank you! : )

☑️ Self-Check before Merge

Self-Tested with cargo run and curl -x http://127.0.0.1:7890 https://httpbin.yba.dev/ip.

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