type ConditionFunc func() (done bool, err error)

// ConditionWithContextFunc returns true if the condition is satisfied, or an error
// if the loop should be aborted.
//
// The caller passes along a context that can be used by the condition function.
type ConditionWithContextFunc func(context.Context) (done bool, err error)

// WithContext converts a ConditionFunc into a ConditionWithContextFunc

// offers all of the functionality of the methods in this package.
func (fn DelayFunc) Until(ctx context.Context, immediate, sliding bool, condition ConditionWithContextFunc) error {
	return loopConditionUntilContext(ctx, &variableTimer{fn: fn, new: internalClock.NewTimer}, immediate, sliding, condition)
}

// context error if the context was terminated.
//
// This is the common loop construct for all polling in the wait package.
func loopConditionUntilContext(ctx context.Context, t Timer, immediate, sliding bool, condition ConditionWithContextFunc) error {
	defer t.Stop()

	var timeCh <-chan time.Time
	doneCh := ctx.Done()

	if !sliding {
		timeCh = t.C()
	}

	// if immediate is true the condition is