Explain Dependency Injection in Go.

Dependency Injection (DI) decouples object creation from business logic, improving testability and modularity.

Unlike Java/C# which rely heavily on massive reflection-based IoC containers (like Spring), Go favors manual DI via constructor functions NewService(db Database). For extremely large codebases, Go developers use code-generation DI (like Google's Wire) or reflection-based DI (like Uber's Dig) to wire up complex dependency graphs automatically.