Explain the use of Go's reflection API for examining the type and value of variables at runtime?

Go's reflection package provides a way to examine the type and value of variables at runtime. This is useful in situations where you don't know the exact type of a value until runtime or when you need to write generic code that can work with different types.

The reflection package provides several functions and types that enable you to examine and manipulate the runtime representation of Go types. Some of the key types and functions in the reflection package include:

• The **reflect.Type** type, which represents the type of a value at runtime.
• The **reflect.Value** type, which represents the value of a variable at runtime.
• The **reflect.TypeOf()** function, which returns the **reflect.Type** of a value.
• The **reflect.ValueOf()** function, which returns the **reflect.Value** of a value.
• The **Value.Kind()** method, which returns the kind of a value (such as **int**, **string**, or **struct**).
• The **Value.Interface()** method, which returns the value of a **reflect.Value** as an **interface{}**.
• The **Value.FieldByName()** method, which returns the value of a named field in a struct.
• The **Value.MethodByName()** method, which returns the value of a named method on a struct.

Using reflection, you can perform a wide range of operations on variables at runtime, such as creating new instances of types, calling methods on structs, and iterating over the fields of a struct.

However, it's important to note that reflection can be slower and less type-safe than other approaches, so it should be used judiciously and only when necessary.