The base class for defining Flink streamlets. Derived classes need to override createLogic to provide the custom implementation for the behavior of the streamlet.

Here's an example:

// new custom `FlinkStreamlet`
class MyFlinkProcessor extends FlinkStreamlet {
  // Step 1: Define inlets and outlets. Note for the outlet you can specify
  //         the partitioner function explicitly or else `RoundRobinPartitioner`
  //         will be used
  val in = AvroInlet[Data]("in")
  val out = AvroOutlet[Simple]("out", _.name)

  // Step 2: Define the shape of the streamlet. In this example the streamlet
  //         has 1 inlet and 1 outlet
  val shape = StreamletShape(in, out)

  // Step 3: Provide custom implementation of `FlinkStreamletLogic` that defines
  //         the behavior of the streamlet
  override def createLogic() = new FlinkStreamletLogic {
    override def executeStreamingQueries = {
      val outStream: DataStream[Simple] =
        writeStream(
          readStream(in).map(r => Simple(r.name)),
          out
        )
      executionEnv.execute()
    }
  }
}