func OutputStart(length time.Duration, out io.Writer) {
	switch useOutput {
	case opt.OutputWAV:
		wav.OutputStart(length, out)
	case opt.OutputNull:
	}
}
OutputStart requires a known length
package bind
import (
	"io"
	"time"
	"github.com/go-mix/mix/bind/hardware/null"
	"github.com/go-mix/mix/bind/opt"
	"github.com/go-mix/mix/bind/sample"
	"github.com/go-mix/mix/bind/sox"
	"github.com/go-mix/mix/bind/spec"
	"github.com/go-mix/mix/bind/wav"
)
func Configure(s spec.AudioSpec) {
	sample.ConfigureOutput(s)
	switch useOutput {
	case opt.OutputWAV:
		wav.ConfigureOutput(s)
	case opt.OutputNull:
		null.ConfigureOutput(s)
	}
}
func IsDirectOutput() bool {
	return useOutput == opt.OutputWAV
}
func SetOutputCallback(fn sample.OutNextCallbackFunc) {
	sample.SetOutputCallback(fn)
}