private void Process(TagHelperContent output, string source)
        {
            var reader  = new SourceReader(source);
            var builder = new StringBuilder();

            while (reader.MoveNext())
            {
                if (reader.Current == '<' && reader.IsTag())
                {//读取html标签
                    ReadHtml(output, builder, reader);
                    continue;
                }

                if (reader.Current == '$' && reader.IsNextNonWhiteSpace('{'))
                {//代码块
                    Queue(output, builder);
                    ReadInlineCode(output, reader);
                    continue;
                }

                if (reader.Current == '`')
                {//字符串
                    ReadQuote(output, builder, reader);
                    continue;
                }

                if (reader.Current == '<')
                {//代码里的小于号if(i < 0){}
                    output.AppendHtml("<");
                    reader.Skip();
                    continue;
                }

                var code = reader.ReadUntil(new[] { '`', '<' }).Trim();
                foreach (var s in code.Split(new[] { "\n" }, StringSplitOptions.RemoveEmptyEntries))
                {
                    if (string.IsNullOrWhiteSpace(s))
                    {
                        continue;
                    }
                    output.AppendHtml(s.Trim());
                }
            }
        }