type LockingMutable interface {
	Mutable

	// SetLocked is like Set but the caller must already hold the lock
	SetLocked(interface{})

	// GetLocked is like Get but the caller must already hold the lock
	GetLocked() interface{}
}

type Mutable interface {

	// Set writes a value into this variable and unblocks every
	// goroutine waiting for this variable to have a value
	Set(interface{})

	// Get reads the value of this variable.  If this variable is
	// not set yet then this call blocks until this variable gets a value.
	Get() interface{}
}