diff --git a/SSignalKit.xcodeproj/project.pbxproj b/SSignalKit.xcodeproj/project.pbxproj
index 39fd44186c..9d389f62c6 100644
--- a/SSignalKit.xcodeproj/project.pbxproj
+++ b/SSignalKit.xcodeproj/project.pbxproj
@@ -88,6 +88,7 @@
 		D06F106C1A85561E00485185 /* SSignalBasicTests.m in Sources */ = {isa = PBXBuildFile; fileRef = D06F106B1A85561E00485185 /* SSignalBasicTests.m */; };
 		D06F10711A855E2D00485185 /* DeallocatingObject.m in Sources */ = {isa = PBXBuildFile; fileRef = D06F10701A855E2D00485185 /* DeallocatingObject.m */; };
 		D06F10731A85882000485185 /* SSignalPerformanceTests.m in Sources */ = {isa = PBXBuildFile; fileRef = D06F10721A85882000485185 /* SSignalPerformanceTests.m */; };
+		D07A5CFD1BBDE6E400451791 /* Promise.swift in Sources */ = {isa = PBXBuildFile; fileRef = D07A5CFC1BBDE6E400451791 /* Promise.swift */; };
 		D09FD73E1BA9BAB900FF0A4F /* SVariable.h in Headers */ = {isa = PBXBuildFile; fileRef = D09FD73C1BA9BAB900FF0A4F /* SVariable.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		D09FD73F1BA9BAB900FF0A4F /* SVariable.m in Sources */ = {isa = PBXBuildFile; fileRef = D09FD73D1BA9BAB900FF0A4F /* SVariable.m */; };
 /* End PBXBuildFile section */
@@ -199,6 +200,7 @@
 		D06F106F1A855E2D00485185 /* DeallocatingObject.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = DeallocatingObject.h; sourceTree = "<group>"; };
 		D06F10701A855E2D00485185 /* DeallocatingObject.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = DeallocatingObject.m; sourceTree = "<group>"; };
 		D06F10721A85882000485185 /* SSignalPerformanceTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SSignalPerformanceTests.m; sourceTree = "<group>"; };
+		D07A5CFC1BBDE6E400451791 /* Promise.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Promise.swift; sourceTree = "<group>"; };
 		D09FD73C1BA9BAB900FF0A4F /* SVariable.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SVariable.h; sourceTree = "<group>"; };
 		D09FD73D1BA9BAB900FF0A4F /* SVariable.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SVariable.m; sourceTree = "<group>"; };
 /* End PBXFileReference section */
@@ -260,6 +262,7 @@
 				D0085B4C1B282BEE00EAF753 /* Disposable.swift */,
 				D0085B4D1B282BEE00EAF753 /* Signal_Mapping.swift */,
 				D0085B4E1B282BEE00EAF753 /* Subscriber.swift */,
+				D07A5CFC1BBDE6E400451791 /* Promise.swift */,
 				D0085B261B282B9800EAF753 /* SwiftSignalKit.h */,
 				D0085B241B282B9800EAF753 /* Supporting Files */,
 			);
@@ -615,6 +618,7 @@
 				D0085B601B282BEE00EAF753 /* Disposable.swift in Sources */,
 				D0085B531B282BEE00EAF753 /* ThreadPool.swift in Sources */,
 				D0085B5F1B282BEE00EAF753 /* Signal.swift in Sources */,
+				D07A5CFD1BBDE6E400451791 /* Promise.swift in Sources */,
 				D0085B5E1B282BEE00EAF753 /* Signal_Reduce.swift in Sources */,
 				D0085B621B282BEE00EAF753 /* Subscriber.swift in Sources */,
 				D0085B581B282BEE00EAF753 /* Signal_Take.swift in Sources */,
diff --git a/SwiftSignalKit/Promise.swift b/SwiftSignalKit/Promise.swift
new file mode 100644
index 0000000000..00e96b9649
--- /dev/null
+++ b/SwiftSignalKit/Promise.swift
@@ -0,0 +1,60 @@
+import Foundation
+
+public class Promise<T> {
+    private var value: T?
+    private var lock: OSSpinLock = 0
+    private let disposable = MetaDisposable()
+    private let subscribers = Bag<T -> Void>()
+    
+    public init(_ value: T) {
+        self.value = value
+    }
+    
+    public init() {
+    }
+
+    deinit {
+        self.disposable.dispose()
+    }
+    
+    public func set(signal: Signal<T, NoError>) {
+        OSSpinLockLock(&self.lock)
+        self.value = nil
+        OSSpinLockUnlock(&self.lock)
+
+        self.disposable.set(signal.start(next: { [weak self] next in
+            if let strongSelf = self {
+                OSSpinLockLock(&strongSelf.lock)
+                strongSelf.value = next
+                let subscribers = strongSelf.subscribers.copyItems()
+                OSSpinLockUnlock(&strongSelf.lock);
+                
+                for subscriber in subscribers {
+                    subscriber(next)
+                }
+            }
+        }))
+    }
+
+    public func get() -> Signal<T, NoError> {
+        return Signal { subscriber in
+            OSSpinLockLock(&self.lock)
+            let currentValue = self.value
+            let index = self.subscribers.add({ next in
+                subscriber.putNext(next)
+            })
+            OSSpinLockUnlock(&self.lock)
+            
+
+            if let currentValue = currentValue {
+                subscriber.putNext(currentValue)
+            }
+
+            return ActionDisposable {
+                OSSpinLockLock(&self.lock)
+                self.subscribers.remove(index)
+                OSSpinLockUnlock(&self.lock)
+            }
+        }
+    }
+}
diff --git a/SwiftSignalKit/Queue.swift b/SwiftSignalKit/Queue.swift
index fa46930ae6..178903b22d 100644
--- a/SwiftSignalKit/Queue.swift
+++ b/SwiftSignalKit/Queue.swift
@@ -3,6 +3,8 @@ import Foundation
 private let _QueueSpecificKey = NSObject()
 private let QueueSpecificKey: UnsafePointer<Void> = UnsafePointer<Void>(Unmanaged<AnyObject>.passUnretained(_QueueSpecificKey).toOpaque())
 
+private let globalMainQueue = Queue(queue: dispatch_get_main_queue(), specialIsMainQueue: true)
+
 public final class Queue {
     private let nativeQueue: dispatch_queue_t
     private var specific: UnsafeMutablePointer<Void>
@@ -15,7 +17,7 @@ public final class Queue {
     }
     
     public class func mainQueue() -> Queue {
-        return Queue(queue: dispatch_get_main_queue(), specialIsMainQueue: true)
+        return globalMainQueue
     }
     
     public class func concurrentDefaultQueue() -> Queue {