code: private void skipCommaSpaces() throws IOException {
          wsp1: for (;;) {
              switch (current) {
                  default:
                      break wsp1;
                  case 0x20:
                  case 0x9:
                  case 0xD:
                  case 0xA:
              }
              current = reader.read();
              appendToContext(current);
          }
          if (current == ',') {
              wsp2: for (;;) {
                  switch (current = reader.read()) {
                      default:
                          appendToContext(current);
                          break wsp2;
                      case 0x20:
                      case 0x9:
                      case 0xA:
                      case 0xD:
                          appendToContext(current);
                  }
              }
          }
      }
docs: Skips the whitespaces and an optional comma.