Function itoa

zlog/logger_core.go:433–454

Convert an integer to a fixed-length string, where the width of the string should be greater than 0 Ensure that the buffer has sufficient capacity (将一个整形转换成一个固定长度的字符串，字符串宽度应该是大于0的 要确保buffer是有容量空间的)

(buf *bytes.Buffer, i int, wID int)

// (将一个整形转换成一个固定长度的字符串，字符串宽度应该是大于0的
// 要确保buffer是有容量空间的)
func itoa(buf *bytes.Buffer, i int, wID int) {
	var u uint = uint(i)
	if u == 0 && wID <= 1 {
		buf.WriteByte('0')
		return
	}

	// Assemble decimal in reverse order.
	var b [32]byte
	bp := len(b)
	for ; u > 0 || wID > 0; u /= 10 {
		bp--
		wID--
		b[bp] = byte(u%10) + '0'
	}

	// avoID slicing b to avoID an allocation.
	for bp < len(b) {
		buf.WriteByte(b[bp])
		bp++
	}
}