code: public Observable<ByteBuf> failoverLogs(Short... vbids) {
      List<Short> partitions = partitionsForVbids(numPartitions(), vbids);
  
      LOGGER.debug("Asking for failover logs on partitions {}", partitions);
  
      return Observable
          .from(partitions)
          .flatMapSingle(new Func1<Short, Single<ByteBuf>>() {
            @Override
            public Single<ByteBuf> call(Short p) {
              return conductor.getFailoverLog(p);
            }
          });
    }
docs: Helper method to return the failover logs for the given partitions (vbids).
  <p>
  If the list is empty, the failover logs for all partitions will be returned. Note that the returned
  ByteBufs can be analyzed using the {@link DcpFailoverLogResponse} flyweight.
  
  @param vbids the partitions to return the failover logs from.
  @return an {@link Observable} containing all failover logs.