log pipe failures, may give clue to blocking output

Author: BrandonArp

src/main/java/com/arpnetworking/tsdcore/sinks/HttpSinkActor.java

@@ -17,6 +17,7 @@
 
 import akka.actor.AbstractActor;
 import akka.actor.Props;
+import akka.actor.Status;
 import akka.pattern.Patterns;
 import com.arpnetworking.logback.annotations.LogValue;
 import com.arpnetworking.metrics.incubator.PeriodicMetrics;
@@ -236,6 +237,13 @@ public Receive createReceive() {
                     _waiting = false;
                     dispatchPending();
                 })
+                .match(Status.Failure.class, message -> {
+                    LOGGER.error()
+                            .setMessage("Received Status.Failure message")
+                            .addContext("actor", self())
+                            .setThrowable(message.cause())
+                            .log();
+                })
                 .matchAny(message -> {
                     LOGGER.error()
                             .setMessage("Unexpected message")