code: @SuppressWarnings("fallthrough")
      protected void quotedString() {
          int pos = bp;
          nextChar();
  
          loop:
          while (bp < buflen) {
              switch (ch) {
                  case '\n': case '\r': case '\f':
                      newline = true;
                      break;
  
                  case ' ': case '\t':
                      break;
  
                  case '"':
                      nextChar();
                      // trim trailing white-space?
                      return;
  
                  case '@':
                      if (newline)
                          break loop;
  
              }
              nextChar();
          }
      }
docs: Read a quoted string.
  It is an error if the beginning of the next tag is detected.