判断一个char[]里是否包含两个连续的\r\n

      public static int ContainsHeaderEndToken(char[] chars, int start, int end) {
            bool secondBackslashN = false;
            bool firstBackslashR = false;
            char expectNextChar = '\r';
            for (int i = start; i < end; i++) {
                if (firstBackslashR && chars[i] != expectNextChar)
                {
                    firstBackslashR = false;
                }
                if (chars[i] != expectNextChar) continue;
                if (expectNextChar == '\r')
                {
                    firstBackslashR = true;
                    expectNextChar = '\n';
                    continue;
                }
                if(expectNextChar == '\n')
                {
                    if(!secondBackslashN)
                    {
                        expectNextChar = '\r';
                        secondBackslashN = true;
                        continue;
                    }
                    return i-4;
                }
            }
            return -1;
        }