Read files with akka stream

    import akka.stream.scaladsl.{Flow, Framing}

    // Given a stream of bytestrings delimited by the system line separator we can get lines represented as Strings
    val lines = Flow[ByteString]
      .via(Framing.delimiter(ByteString(System.lineSeparator), 10000, allowTruncation = true))
      .map(bs => bs.utf8String)

    // given as stream of Paths we read those files and count the number of lines
    val lineCounter = Flow[Path]
      .flatMapConcat(path => FileIO.fromPath(path).via(lines))
      .fold(0l)((count, line) => count + 1)
      .toMat(Sink.head)(Keep.right)

    // Here's our test data source (replace paths with real paths)
    val testFiles = Source(List("somePathToFile1", "somePathToFile2").map(new File(_).toPath))

    // Runs the line counter over the test files, returns a Future, which contains the number of lines, which we then print out to the console when it completes
    testFiles.runWith(lineCounter).foreach(println)