Add dedupeBatch: collapse outbound calls per target

src/AFRP.hs

@@ -52,7 +52,7 @@ data Request = Request
   { requestTime :: !UTCTime
   , requestTimeZone :: !TimeZone
   , requestTraceId :: !UUID
-  } deriving Show
+  } deriving (Show, Eq)
 
 -- | The set of entity ids an arrow subscribes to. Static: it does not
 -- change as the machine steps, so the runtime can read it once to build