code: public String getStringOutput(String appenderName, String encoding) throws UnsupportedEncodingException {
  		AdminToolLog4j2OutputStream baos = outputStreams.get(appenderName);
  		String output = "";
  		if (null != baos) {
  			output = baos.getAndReset(encoding);
  		}
  		return output.trim().isEmpty() ? null : output;
  		
  	}
docs: returns the log messages from custom appenders output stream
  
  @param appenderName
  @param encoding
  @return
  @throws UnsupportedEncodingException
  @since 1.1.1