Permit setting deadline per-call

Adds a setDeadline method to the request builder, so that it can optionally be
specified per call.

runtime/src/main/scala/akka/grpc/internal/RequestBuilderImpl.scala

@@ -4,11 +4,11 @@
 
 package akka.grpc.internal
 
-import java.util.concurrent.CompletionStage
-
+import java.util.concurrent.{ CompletionStage, TimeUnit }
 import akka.NotUsed
 import akka.annotation.{ InternalApi, InternalStableApi }
 import akka.dispatch.ExecutionContexts
+import akka.grpc.scaladsl.SingleResponseRequestBuilder
 import akka.grpc.{ GrpcClientSettings, GrpcResponseMetadata, GrpcServiceException, GrpcSingleResponse }
 import akka.stream.{ Graph, Materializer, SourceShape }
 import akka.stream.javadsl.{ Source => JavaSource }
@@ -17,6 +17,7 @@ import akka.util.ByteString
 import io.grpc._
 
 import scala.compat.java8.FutureConverters._
+import scala.concurrent.duration.Duration
 import scala.concurrent.{ ExecutionContext, Future }
 
 /**
@@ -52,6 +53,14 @@ final class ScalaUnaryRequestBuilder[I, O](
 
   override def withHeaders(headers: MetadataImpl): ScalaUnaryRequestBuilder[I, O] =
     new ScalaUnaryRequestBuilder[I, O](descriptor, channel, defaultOptions, settings, headers)
+
+  override def setDeadline(deadline: Duration): SingleResponseRequestBuilder[I, O] =
+    new ScalaUnaryRequestBuilder[I, O](
+      descriptor,
+      channel,
+      defaultOptions.withDeadlineAfter(deadline.toMillis, TimeUnit.MILLISECONDS),
+      settings,
+      headers)
 }
 
 /**
@@ -152,6 +161,14 @@ final class ScalaClientStreamingRequestBuilder[I, O](
 
   override def withHeaders(headers: MetadataImpl): ScalaClientStreamingRequestBuilder[I, O] =
     new ScalaClientStreamingRequestBuilder[I, O](descriptor, channel, defaultOptions, settings, headers)
+
+  override def setDeadline(deadline: Duration): ScalaClientStreamingRequestBuilder[I, O] =
+    new ScalaClientStreamingRequestBuilder[I, O](
+      descriptor,
+      channel,
+      defaultOptions.withDeadlineAfter(deadline.toMillis, TimeUnit.MILLISECONDS),
+      settings,
+      headers)
 }
 
 /**

runtime/src/main/scala/akka/grpc/scaladsl/RequestBuilder.scala

@@ -11,6 +11,7 @@ import akka.stream.scaladsl.Source
 import akka.util.ByteString
 
 import scala.concurrent.Future
+import scala.concurrent.duration.Duration
 
 /**
  * Request builder for requests providing per call specific metadata capabilities in
@@ -48,6 +49,12 @@ trait SingleResponseRequestBuilder[Req, Res] {
    * Invoke the gRPC method with the additional metadata added and provide access to response metadata
    */
   def invokeWithMetadata(request: Req): Future[GrpcSingleResponse[Res]]
+
+  /**
+   * Set the deadline for this call
+   * @return A new request builder, that will use the supplied deadline when invoked
+   */
+  def setDeadline(deadline: Duration): SingleResponseRequestBuilder[Req, Res]
 }
 
 /**