code: public static Collection<ContentStream> toContentStreams(final String str, final String contentType) {
  
          if (str == null) {
              return null;
          }
  
          ArrayList<ContentStream> streams = new ArrayList<>(1);
          ContentStreamBase ccc = new ContentStreamBase.StringStream(str);
          ccc.setContentType(contentType);
          streams.add(ccc);
          return streams;
      }
docs: Take a string and make it an iterable ContentStream