code: @VisibleForTesting
    static void appendSpaces(StringBuilder sb, int numSpaces) {
      if (numSpaces > 16) {
        logger.warning("Tracer.appendSpaces called with large numSpaces");
        // Avoid long loop in case some bug in the caller
        numSpaces = 16;
      }
      while (numSpaces >= 5) {
        sb.append("     ");
        numSpaces -= 5;
      }
  
      // We know it's less than 5 now
      switch (numSpaces) {
        case 1:
          sb.append(" ");
          break;
        case 2:
          sb.append("  ");
          break;
        case 3:
          sb.append("   ");
          break;
        case 4:
          sb.append("    ");
          break;
      }
    }
docs: Gets a string of spaces of the length specified.
  @param sb The string builder to append to.
  @param numSpaces The number of spaces in the string.