Add a utility to produce transaction responses.

lib/wire/util.js

@@ -37,6 +37,36 @@ var wireutil = {
       )
       .encodeNB()
   }
+, response: function(source) {
+    var seq = 0
+    return {
+      okay: function(data, body) {
+        return wireutil.envelope(new wire.TransactionDoneMessage(
+          source
+        , seq++
+        , true
+        , data
+        , body ? JSON.stringify(body) : null
+        ))
+      }
+    , fail: function(data) {
+        return wireutil.envelope(new wire.TransactionDoneMessage(
+          source
+        , seq++
+        , false
+        , data
+        ))
+      }
+    , progress: function(data, progress) {
+        return wireutil.envelope(new wire.TransactionProgressMessage(
+          source
+        , seq++
+        , data
+        , progress
+        ))
+      }
+    }
+  }
 }
 
 module.exports = wireutil