code: protected RequestEntity createStringRequestContent(HTTPRequest httpRequest)
      {
          RequestEntity requestEntity=null;
          String contentString=httpRequest.getContentAsString();
          if(contentString!=null)
          {
              try
              {
                  requestEntity=new StringRequestEntity(contentString,"text/plain",null);
              }
              catch(UnsupportedEncodingException exception)
              {
                  throw new FaxException("Unable to set string request entity.",exception);
              }
          }
          
          return requestEntity;
      }
docs: This function creates a string type request entity and populates it
  with the data from the provided HTTP request.
  
  @param   httpRequest
  The HTTP request
  @return  The request entity