How do you implement the Drop trait?

Question

Accepted Answer

**Drop** — custom cleanup on value going out of scope.

**Implementation:**
```rust
struct MyResource {
    data: Vec<u8>,
}

impl Drop for MyResource {
    fn drop(&mut self) {
        println!("Dropping resource with {} bytes", self.data.len());
        // Cleanup here
    }
}

{
    let r = MyResource { data: vec![0; 1024] };
    // Using resource...
}  // drop() called here
```

**Drop order:**
```rust
let a = MyResource { data: vec![] };
let b = MyResource { data: vec![] };
drop(a);  // Explicit drop
// b dropped at end of scope
```

**Key:** Drop for RAII, called automatically.

Rust: How do you implement the Drop trait?