Merge stream elements into one http chunk

Streams are great but I got a stream of thousand elements. Unfortunately every element is emitted in one http chunk (and the elements are small). Would be nice if the framework supports "merging" of multiple elements into one chunk and return a valid json array of elements.

My workaround

                      def toJsonBytes(source: Seq[T]): ByteString =
                        ByteString(source.map(t => t.asJson.noSpaces).mkString(","))
                      // emit 100 elements in one http chunk
                      val chunk = t.groupedWithin(100, 100.millis)
                      val fst   = Flow[Seq[T]].map(toJsonBytes)
                      val rst   = Flow[Seq[T]].map(ByteString(",") ++ toJsonBytes(_))
                      val together = chunk.prefixAndTail(1).flatMapConcat {
                        case (head, tail) =>
                          Source(head).via(fst).concat(tail.via(rst))
                      }
                      complete(
                        HttpEntity(
                          ContentTypes.`application/json`,
                          Source.single(ByteString("[")) ++ together ++ Source.single(ByteString("]"))
                        )
                      )