diff --git a/src/io/v3/address.hpp b/src/io/v3/address.hpp
index 4738d3042..4e1a80c75 100644
--- a/src/io/v3/address.hpp
+++ b/src/io/v3/address.hpp
@@ -11,6 +11,8 @@
 
 #pragma once
 
+#include <compare>
+
 #include <boost/asio/ip/tcp.hpp>
 #include <boost/uuid/uuid.hpp>
 
@@ -31,4 +33,16 @@ struct Address {
     ret.last_known_port = port;
     return ret;
   }
+
+  bool operator==(const Address &other) const {
+    return (last_known_ip == other.last_known_ip) && (last_known_port == other.last_known_port);
+  }
+
+  bool operator<(const Address &other) const {
+    if (last_known_ip == other.last_known_ip) {
+      return last_known_port < other.last_known_port;
+    } else {
+      return last_known_ip < other.last_known_ip;
+    }
+  }
 };
diff --git a/src/io/v3/future.hpp b/src/io/v3/future.hpp
index 48fc1f9bc..4b0e188db 100644
--- a/src/io/v3/future.hpp
+++ b/src/io/v3/future.hpp
@@ -159,6 +159,8 @@ class MgPromise {
   friend std::pair<MgFuture<T>, MgPromise<T>> FuturePromisePairWithNotifier<T>(std::function<void()>);
 
  public:
+  MgPromise(std::shared_ptr<Shared<T>> shared) : shared_(shared) {}
+
   MgPromise(MgPromise &&old) {
     shared_ = std::move(old.shared_);
     MG_ASSERT(!old.filled_or_moved_, "MgPromise moved from after already being moved from or filled.");
@@ -183,9 +185,16 @@ class MgPromise {
 
   bool IsAwaited() { return shared_->IsAwaited(); }
 
- private:
-  MgPromise(std::shared_ptr<Shared<T>> shared) : shared_(shared) {}
+  /// Moves this MgPromise into a unique_ptr.
+  std::unique_ptr<MgPromise<T>> ToUnique() && {
+    std::unique_ptr<MgPromise<T>> up = std::make_unique<MgPromise<T>>(std::move(shared_));
 
+    filled_or_moved_ = true;
+
+    return up;
+  }
+
+ private:
   std::shared_ptr<Shared<T>> shared_;
   bool filled_or_moved_ = false;
 };
diff --git a/src/io/v3/simulator.hpp b/src/io/v3/simulator.hpp
index e5522c813..40fef63ef 100644
--- a/src/io/v3/simulator.hpp
+++ b/src/io/v3/simulator.hpp
@@ -41,12 +41,12 @@ class SimulatorTransport {
     return std::move(future);
   }
 
-  /*
-    template <Message... Ms>
-    RequestResult<Ms...> Receive(uint64_t timeout_microseconds) {
-      return simulator_handle_->template Receive<Ms...>(timeout_microseconds);
-    }
+  template <Message... Ms>
+  RequestResult<Ms...> Receive(uint64_t timeout_microseconds) {
+    return simulator_handle_->template Receive<Ms...>(timeout_microseconds);
+  }
 
+  /*
     template <Message M>
     void Send(Address address, uint64_t request_id, M message) {
       return simulator_handle_->template Send<M>(address, request_id, message);
@@ -69,5 +69,5 @@ class Simulator {
   }
 
  private:
-  std::shared_ptr<SimulatorHandle> simulator_handle_;
+  std::shared_ptr<SimulatorHandle> simulator_handle_{std::make_shared<SimulatorHandle>()};
 };
diff --git a/src/io/v3/simulator_handle.hpp b/src/io/v3/simulator_handle.hpp
index 9e0e73d9b..e6b761fe7 100644
--- a/src/io/v3/simulator_handle.hpp
+++ b/src/io/v3/simulator_handle.hpp
@@ -11,6 +11,7 @@
 
 #pragma once
 
+#include <compare>
 #include <map>
 #include <vector>
 
@@ -28,11 +29,71 @@ struct PromiseKey {
   Address requester;
   uint64_t request_id;
   Address replier;
+
+ public:
+  bool operator<(const PromiseKey &other) const {
+    if (requester == other.requester) {
+      return request_id < other.request_id;
+    } else {
+      return requester < other.requester;
+    }
+  }
 };
 
-struct OpaquePromise {
+// TODO delete copy ctor & copy assignment operator if possible
+class OpaquePromise {
+ public:
+  OpaquePromise(OpaquePromise &&old) : ti_(old.ti_) {
+    ptr_ = old.ptr_;
+    old.ptr_ = nullptr;
+  }
+
+  OpaquePromise &operator=(OpaquePromise &&old) {
+    MG_ASSERT(this != &old);
+
+    ptr_ = old.ptr_;
+    ti_ = old.ti_;
+    old.ptr_ = nullptr;
+
+    return *this;
+  }
+
+  OpaquePromise(const OpaquePromise &) = delete;
+  OpaquePromise &operator=(const OpaquePromise &) = delete;
+
+  template <typename T>
+  std::unique_ptr<MgPromise<T>> Take() {
+    MG_ASSERT(typeid(T) == *ti_);
+    MG_ASSERT(ptr_ != nullptr);
+
+    MgPromise<T> *ptr = static_cast<MgPromise<T> *>(ptr_);
+
+    ptr_ = nullptr;
+
+    return std::unique_ptr<T>(ptr);
+  }
+
+  template <typename T>
+  OpaquePromise(std::unique_ptr<MgPromise<T>> promise)
+      : ti_(&typeid(T)),
+        ptr_((void *)promise.release()),
+        dtor_([](void *ptr) { static_cast<MgPromise<T> *>(ptr)->~MgPromise<T>(); }) {}
+
+  ~OpaquePromise() {
+    if (nullptr != ptr_) {
+      dtor_(ptr_);
+    }
+  }
+
+ private:
+  const std::type_info *ti_;
+  void *ptr_;
+  std::function<void(void *)> dtor_;
+};
+
+struct DeadlineAndOpaquePromise {
   uint64_t deadline;
-  std::any promise;
+  OpaquePromise promise;
 };
 
 class SimulatorHandle {
@@ -58,12 +119,10 @@ class SimulatorHandle {
     OpaqueMessage om{.address = from_addr, .request_id = request_id, .message = std::move(message)};
     in_flight_.emplace_back(std::make_pair(std::move(to_addr), std::move(om)));
 
-    /*
-    std::any opaque_promise(std::move(promise));
-    PromiseKey pk { .requester=from_addr, .request_id=request_id, .replier=to_addr };
-    OpaquePromise op { .deadline=deadline, .promise=std::move(opaque_promise) };
-    promises_.insert(std::make_pair(std::move(pk), std::move(op)));
-    */
+    OpaquePromise opaque_promise(std::move(promise).ToUnique());
+    PromiseKey pk{.requester = from_addr, .request_id = request_id, .replier = to_addr};
+    DeadlineAndOpaquePromise op{.deadline = deadline, .promise = std::move(opaque_promise)};
+    promises_.emplace(std::move(pk), std::move(op));
 
     stats_.total_messages_++;
     stats_.total_requests_++;
@@ -71,11 +130,11 @@ class SimulatorHandle {
     return;
   }
 
+  template <Message... Ms>
+  RequestResult<Ms...> Receive(uint64_t timeout_microseconds) {
+    std::terminate();
+  }
   /*
-    template <Message... Ms>
-    RequestResult<Ms...> Receive(uint64_t timeout_microseconds) {
-      std::abort();
-    }
 
     template <Message M>
     void Send(Address address, uint64_t request_id, M message) {
@@ -84,11 +143,11 @@ class SimulatorHandle {
     */
 
  private:
-  std::mutex mu_;
+  std::mutex mu_{};
   std::condition_variable cv_sim_;
   std::condition_variable cv_srv_;
   std::vector<std::pair<Address, OpaqueMessage>> in_flight_;
-  std::map<PromiseKey, OpaquePromise> promises_;
+  std::map<PromiseKey, DeadlineAndOpaquePromise> promises_;
   std::map<Address, OpaqueMessage> can_receive_;
   uint64_t cluster_wide_time_microseconds_ = 0;
   bool shut_down_;
diff --git a/src/io/v3/transport.hpp b/src/io/v3/transport.hpp
index 348529e74..40f3cd125 100644
--- a/src/io/v3/transport.hpp
+++ b/src/io/v3/transport.hpp
@@ -9,6 +9,8 @@
 // by the Apache License, Version 2.0, included in the file
 // licenses/APL.txt.
 
+// TODO chrono::microseconds instead of std::time_t
+
 #pragma once
 
 #include <concepts>
@@ -61,13 +63,13 @@ class Io {
  public:
   Io(I io, Address address) : implementation_(io), address_(address) {}
 
-  /// Set the default time-out for all requests that are issued
-  /// without an explicit time-out set.
+  /// Set the default timeout for all requests that are issued
+  /// without an explicit timeout set.
   void SetDefaultTimeoutMicroseconds(uint64_t timeout_microseconds) {
     default_timeout_microseconds_ = timeout_microseconds;
   }
 
-  /// Issue a request with an explicit time-out in microseconds provided.
+  /// Issue a request with an explicit timeout in microseconds provided.
   template <Message Request, Message Response>
   ResponseFuture<Response> RequestWithTimeout(Address address, Request request, uint64_t timeout_microseconds) {
     uint64_t request_id = ++request_id_counter_;
diff --git a/tests/simulation/basic_request.cpp b/tests/simulation/basic_request.cpp
index b4dd7b532..40a756a71 100644
--- a/tests/simulation/basic_request.cpp
+++ b/tests/simulation/basic_request.cpp
@@ -14,8 +14,6 @@
 #include <string>
 #include <vector>
 
-#include <spdlog/spdlog.h>
-
 #include "io/v3/simulator.hpp"
 #include "utils/terminate_handler.hpp"
 
@@ -47,8 +45,8 @@ int main() {
   RequestMsg cli_req;
   ResponseFuture<ResponseMsg> response_future = cli_io.template Request<RequestMsg, ResponseMsg>(srv_addr, cli_req);
 
-  //  // receive request
-  //  RequestResult<Request> request_result = sim_io_2.template ReceiveTimeout<Request>();
+  // receive request
+  RequestResult<RequestMsg> request_result = srv_io.template Receive<RequestMsg>();
   //  auto req_envelope = request_result.GetValue();
   //  Request req = std::get<Request>(req_envelope.message);
   //