Logging with `tap`

The tap method allows you to observe values flowing through your pipeline without modifying them. This is useful for logging, debugging, or collecting metrics.

import etl4s._

val sayHello   = Extract("hello world")
val splitWords = Transform[String, Array[String]](_.split(" "))

val pipeline = sayHello ~> 
               tap((x: String) => println(s"Processing: $x")) ~>
               splitWords

val result = pipeline.unsafeRun(())

This will return Array("hello", "world") and also prints to stdout Processing: hello world