code: @Path("/{dsID}/content")
      @GET
      public Response getDatastream(@PathParam(RestParam.PID) String pid,
                                    @PathParam(RestParam.DSID) String dsID,
                                    @QueryParam(RestParam.AS_OF_DATE_TIME) String dateTime,
                                    @QueryParam(RestParam.DOWNLOAD) String download,
                                    @QueryParam(RestParam.FLASH) @DefaultValue("false") boolean flash) {
          Context context = getContext();
          try {
              Date asOfDateTime = DateUtility.parseDateOrNull(dateTime);
              MIMETypedStream stream =
                      m_access.getDatastreamDissemination(context,
                                                             pid,
                                                             dsID,
                                                             asOfDateTime);
              if (m_datastreamFilenameHelper != null) {
                  m_datastreamFilenameHelper
                          .addContentDispositionHeader(context,
                                                       pid,
                                                       dsID,
                                                       download,
                                                       asOfDateTime,
                                                       stream);
  
              }
  
              return buildResponse(stream);
          } catch (Exception ex) {
              return handleException(ex, flash);
          }
      }
docs: <p>Invoke API-A.getDatastreamDissemination(context, pid, dsID, asOfDateTime)
  </p><p>
  GET /objects/{pid}/datastreams/{dsID}/content ? asOfDateTime</p>