docs: @GET
      @Path("/{ccid: [A-Z,a-z,0-9,_,\\-,\\.]+}")
      @Produces({ MediaType.APPLICATION_JSON })
      @Suspend(resumeOnBroadcast = true, period = ChannelServiceConstants.EXPIRE_TIME_CONNECTION,
               timeUnit = TimeUnit.SECONDS, contentType = MediaType.APPLICATION_JSON)
      public Broadcastable open(@PathParam("ccid") String ccid,
                                @HeaderParam("X-Cache-Index") Integer cacheIndex,
                                @HeaderParam(ChannelServiceConstants.X_ATMOSPHERE_TRACKING_ID) String atmosphereTrackingId) {
  
          try {
              return channelService.openChannel(ccid, cacheIndex, atmosphereTrackingId);
          } catch (WebApplicationException e) {
              throw e;
          } catch (Exception e) {
              log.error("GET Channels open long poll ccid: error: {}", e.getMessage(), e);
              throw new WebApplicationException(Status.INTERNAL_SERVER_ERROR);
          }
      }