Go

Patterns

To ensure interface cannot be implemented in other packages, add a private function (first character must be lower-case) named "is" + type name, which takes no arguments, returns nothing, and has an empty body.

For example:
```
type I interface {
    isI()
}
```
See https://go.dev/doc/faq#guarantee_satisfies_interface
To ensure a type implements an interface at compile-time, use the "interface guard" pattern: Introduce a global variable named _, type it as the interface, and assign an empty value of the concrete type to it.

For example:
```
type T struct {
    //...
}

var _ io.ReadWriter = (*T)(nil)

func (t *T) Read(p []byte) (n int, err error) {
// ...
```
See