func (stream *Stream) WriteUint8(val uint8) {
	stream.ensure(3)
	stream.n = writeFirstBuf(stream.buf, digits[val], stream.n)
}
WriteUint8 write uint8 to stream
package jsoniter
var digits []uint32
func init() {
	digits = make([]uint32, 1000)
	for i := uint32(0); i < 1000; i++ {
		digits[i] = (((i / 100) + '0') << 16) + ((((i / 10) % 10) + '0') << 8) + i%10 + '0'
		if i < 10 {
			digits[i] += 2 << 24
		} else if i < 100 {
			digits[i] += 1 << 24
		}
	}
}
func writeFirstBuf(buf []byte, v uint32, n int) int {
	start := v >> 24
	if start == 0 {
		buf[n] = byte(v >> 16)
		n++
		buf[n] = byte(v >> 8)
		n++
	} else if start == 1 {
		buf[n] = byte(v >> 8)
		n++
	}
	buf[n] = byte(v)
	n++
	return n
}
func writeBuf(buf []byte, v uint32, n int) {
	buf[n] = byte(v >> 16)
	buf[n+1] = byte(v >> 8)
	buf[n+2] = byte(v)
}