Go object that stores a value only once

once.go

package once

import "sync"

type Once[T any] struct {
	sync.Mutex
	has bool
	v   T
}

func (o *Once[T]) Store(v T) {
	o.Lock()
	defer o.Unlock()
	if o.has {
		return
	}
	o.v = v
	o.has = true
}

func (o *Once[T]) Load() T {
	o.Lock()
	defer o.Unlock()
	return o.v
}