func (stream *Stream) WriteFloat32(val float32) {
	abs := math.Abs(float64(val))
	fmt := byte('f')
	if abs != 0 {
		if float32(abs) < 1e-6 || float32(abs) >= 1e21 {
			fmt = 'e'
		}
	}
	stream.WriteRaw(strconv.FormatFloat(float64(val), fmt, -1, 32))
}
WriteFloat32 write float32 to stream
package jsoniter
import (
	"math"
	"strconv"
)
var pow10 []uint64
func init() {
	pow10 = []uint64{1, 10, 100, 1000, 10000, 100000, 1000000}
}