code: public String getCauseStackTraceAsString(final List<String> ignorePackages, final TextRenderer textRenderer, final String suffix) {
          final StringBuilder sb = new StringBuilder();
          if (this.causeProxy != null) {
              this.formatWrapper(sb, this.causeProxy, ignorePackages, textRenderer, suffix);
              sb.append(WRAPPED_BY_LABEL);
              renderSuffix(suffix, sb, textRenderer);
          }
          this.renderOn(sb, textRenderer);
          renderSuffix(suffix, sb, textRenderer);
          textRenderer.render(EOL_STR, sb, "Text");
          this.formatElements(sb, Strings.EMPTY, 0, this.throwable.getStackTrace(), this.extendedStackTrace,
                  ignorePackages, textRenderer, suffix);
          return sb.toString();
      }
docs: Formats the Throwable that is the cause of this Throwable.
  
  @param ignorePackages The List of packages to be suppressed from the trace.
  @param textRenderer   the text renderer
  @param suffix
  @return The formatted Throwable that caused this Throwable.