Better Implicits Management

[juanpedromoreno]

At this moment, users of frees-rpc have to define several implicits that are repeated once again.

We could offer them just importing:

import freestyle.rpc.server.implicits._ or import freestyle.rpc.client.implicits._, depending on the case.

For example, something like the following can be provided by the library:

trait FutureInstances extends freestyle.rpc.client.FutureInstances {

  protected val atMostDuration: FiniteDuration = 10.seconds

  implicit def futureComonad(implicit ec: ExecutionContext): Comonad[Future] =
    new Comonad[Future] {
      def extract[A](x: Future[A]): A = {
        logger.info(s"${Thread.currentThread().getName} Waiting $atMostDuration for $x...")
        Await.result(x, atMostDuration)
      }

      override def coflatMap[A, B](fa: Future[A])(f: (Future[A]) => B): Future[B] = Future(f(fa))

      override def map[A, B](fa: Future[A])(f: (A) => B): Future[B] =
        fa.map(f)
    }

  implicit val future2Task: Future ~> Task =
    new (Future ~> Task) {
      override def apply[A](fa: Future[A]): Task[A] = {
        logger.info(s"${Thread.currentThread().getName} Deferring Future to Task...")
        Task.deferFuture(fa)
      }
    }
}

Here, perhaps:

https://github.com/frees-io/freestyle-rpc/blob/5180a8f88785cf55a636bfe18269cbbf6b7b1b2a/rpc/src/main/scala/client/implicits.scala#L28-L35