private static void handleTwoBytes(byte byte1, byte byte2, char[] resultArr, int resultPos) {
            // Simultaneously checks for illegal trailing-byte in leading position (<= '11000000') and
            // overlong 2-byte, '11000001'.
            if (byte1 < (byte) 0xC2 || isNotTrailingByte(byte2)) {
                throw invalidUtf8();
            }
            resultArr[resultPos] = (char) (((byte1 & 0x1F) << 6) | trailingByteValue(byte2));
        }
Returns whether this is a three-byte codepoint with the form '110XXXXX'.
jraft-core/src/main/java/com/alipay/sofa/jraft/util/internal/UnsafeUtf8Util.java