diff --git a/source/tanya/async/event/iocp.d b/source/tanya/async/event/iocp.d
index b6522d9..ff2b4c4 100644
--- a/source/tanya/async/event/iocp.d
+++ b/source/tanya/async/event/iocp.d
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /**
- * Copyright: Eugene Wissner 2016.
+ * Copyright: Eugene Wissner 2016-2017.
  * License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
  *                  Mozilla Public License, v. 2.0).
  * Authors: $(LINK2 mailto:info@caraus.de, Eugene Wissner)
diff --git a/source/tanya/async/event/selector.d b/source/tanya/async/event/selector.d
index 5508cac..0b2143f 100644
--- a/source/tanya/async/event/selector.d
+++ b/source/tanya/async/event/selector.d
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /**
- * Copyright: Eugene Wissner 2016.
+ * Copyright: Eugene Wissner 2016-2017.
  * License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
  *                  Mozilla Public License, v. 2.0).
  * Authors: $(LINK2 mailto:info@caraus.de, Eugene Wissner)
@@ -13,6 +13,7 @@ module tanya.async.event.selector;
 version (Posix):
 
 import tanya.async.loop;
+import tanya.async.protocol;
 import tanya.async.transport;
 import tanya.async.watcher;
 import tanya.container.buffer;
@@ -28,6 +29,8 @@ class SelectorStreamTransport : StreamTransport
 {
 	private ConnectedSocket socket_;
 
+	private Protocol protocol_;
+
 	/// Input buffer.
 	package WriteBuffer!ubyte input;
 
@@ -40,22 +43,64 @@ class SelectorStreamTransport : StreamTransport
 	 * Params:
 	 * 	loop     = Event loop.
 	 * 	socket   = Socket.
+	 * 	protocol = Application protocol.
+	 *
+	 * Precondition: $(D_INLINECODE loop !is null
+	 *                           && socket !is null
+	 *                           && protocol !is null)
 	 */
-	this(SelectorLoop loop, ConnectedSocket socket) @nogc
+	this(SelectorLoop loop, ConnectedSocket socket, Protocol protocol) @nogc
+	in 
+	{
+		assert(loop !is null);
+		assert(socket !is null);
+		assert(protocol !is null);
+	}
+	body
 	{
 		socket_ = socket;
 		this.loop = loop;
+		protocol_ = protocol;
 		input = WriteBuffer!ubyte(8192, MmapPool.instance);
 	}
 
 	/**
 	 * Returns: Transport socket.
 	 */
-	inout(ConnectedSocket) socket() inout pure nothrow @safe @nogc
+	ConnectedSocket socket() pure nothrow @safe @nogc
 	{
 		return socket_;
 	}
 
+	/**
+	 * Returns: Application protocol.
+	 */
+	@property Protocol protocol() pure nothrow @safe @nogc
+	{
+		return protocol_;
+	}
+
+	/**
+	 * Switches the protocol.
+	 *
+	 * The protocol is deallocated by the event loop, it should currently be
+	 * allocated with $(D_PSYMBOL MmapPool).
+	 *
+	 * Params:
+	 * 	protocol = Application protocol.
+	 *
+	 * Precondition: $(D_INLINECODE protocol !is null)
+	 */
+	@property void protocol(Protocol protocol) pure nothrow @safe @nogc
+	in
+	{
+		assert(protocol !is null);
+	}
+	body
+	{
+		protocol_ = protocol;
+	}
+
 	/**
 	 * Write some data to the transport.
 	 *
@@ -224,7 +269,8 @@ abstract class SelectorLoop : Loop
 			}
 
 			IOWatcher io;
-			auto transport = MmapPool.instance.make!SelectorStreamTransport(this, client);
+			auto protocol = connection.protocol;
+			auto transport = MmapPool.instance.make!SelectorStreamTransport(this, client, protocol);
 
 			if (connections.length > client.handle)
 			{
@@ -236,13 +282,12 @@ abstract class SelectorLoop : Loop
 			}
 			if (io is null)
 			{
-				io = MmapPool.instance.make!IOWatcher(transport,
-				                                      connection.protocol);
+				io = MmapPool.instance.make!IOWatcher(transport, protocol);
 				connections[client.handle] = io;
 			}
 			else
 			{
-				io(transport, connection.protocol);
+				io(transport, protocol);
 			}
 
 			reify(io, EventMask(Event.none), EventMask(Event.read, Event.write));
diff --git a/source/tanya/async/iocp.d b/source/tanya/async/iocp.d
index 9730262..0dfcbe8 100644
--- a/source/tanya/async/iocp.d
+++ b/source/tanya/async/iocp.d
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /**
- * Copyright: Eugene Wissner 2016.
+ * Copyright: Eugene Wissner 2016-2017.
  * License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
  *                  Mozilla Public License, v. 2.0).
  * Authors: $(LINK2 mailto:info@caraus.de, Eugene Wissner)
diff --git a/source/tanya/async/package.d b/source/tanya/async/package.d
index 0c5a743..e9ed007 100644
--- a/source/tanya/async/package.d
+++ b/source/tanya/async/package.d
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /**
- * Copyright: Eugene Wissner 2016.
+ * Copyright: Eugene Wissner 2016-2017.
  * License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
  *                  Mozilla Public License, v. 2.0).
  * Authors: $(LINK2 mailto:info@caraus.de, Eugene Wissner)
diff --git a/source/tanya/async/transport.d b/source/tanya/async/transport.d
index d72d42d..6e4460c 100644
--- a/source/tanya/async/transport.d
+++ b/source/tanya/async/transport.d
@@ -3,13 +3,14 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /**
- * Copyright: Eugene Wissner 2016.
+ * Copyright: Eugene Wissner 2016-2017.
  * License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
  *                  Mozilla Public License, v. 2.0).
  * Authors: $(LINK2 mailto:info@caraus.de, Eugene Wissner)
  */
 module tanya.async.transport;
 
+import tanya.async.protocol;
 import tanya.network.socket;
 
 /**
@@ -45,6 +46,33 @@ interface WriteTransport : Transport
  */
 interface DuplexTransport : ReadTransport, WriteTransport
 {
+	/**
+	 * Returns: Application protocol.
+	 *
+	 * Postcondition: $(D_INLINECODE protocol !is null)
+	 */
+	@property Protocol protocol() pure nothrow @safe @nogc
+	out (protocol)
+	{
+		assert(protocol !is null);
+	}
+
+	/**
+	 * Switches the protocol.
+	 *
+	 * The protocol is deallocated by the event loop, it should currently be
+	 * allocated with $(D_PSYMBOL MmapPool).
+	 *
+	 * Params:
+	 * 	protocol = Application protocol.
+	 *
+	 * Precondition: $(D_INLINECODE protocol !is null)
+	 */
+	@property void protocol(Protocol protocol) pure nothrow @safe @nogc
+	in
+	{
+		assert(protocol !is null);
+	}
 }
 
 /**
@@ -52,7 +80,7 @@ interface DuplexTransport : ReadTransport, WriteTransport
  */
 interface SocketTransport : Transport
 {
-	@property inout(Socket) socket() inout pure nothrow @safe @nogc;
+	@property Socket socket() pure nothrow @safe @nogc;
 }
 
 /**
diff --git a/source/tanya/async/watcher.d b/source/tanya/async/watcher.d
index 44b7a1d..de23aa1 100644
--- a/source/tanya/async/watcher.d
+++ b/source/tanya/async/watcher.d
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /**
- * Copyright: Eugene Wissner 2016.
+ * Copyright: Eugene Wissner 2016-2017.
  * License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
  *                  Mozilla Public License, v. 2.0).
  * Authors: $(LINK2 mailto:info@caraus.de, Eugene Wissner)
@@ -90,7 +90,7 @@ class ConnectionWatcher : Watcher
 	/**
 	 * Returns: Socket.
 	 */
-	@property inout(Socket) socket() inout pure nothrow @nogc
+	@property Socket socket() pure nothrow @nogc
 	{
 		return socket_;
 	}
@@ -222,7 +222,7 @@ class IOWatcher : ConnectionWatcher
 	/**
 	 * Returns: Socket.
 	 */
-	override @property inout(Socket) socket() inout pure nothrow @nogc
+	override @property Socket socket() pure nothrow @nogc
 	{
 		return transport.socket;
 	}
diff --git a/source/tanya/container/string.d b/source/tanya/container/string.d
new file mode 100644
index 0000000..05f9e70
--- /dev/null
+++ b/source/tanya/container/string.d
@@ -0,0 +1,77 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Copyright: Eugene Wissner 2016-2017.
+ * License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
+ *                  Mozilla Public License, v. 2.0).
+ * Authors: $(LINK2 mailto:info@caraus.de, Eugene Wissner)
+ */  
+module tanya.container.string;
+
+import core.exception;
+import core.stdc.string;
+import tanya.memory;
+
+/**
+ * UTF-8 string.
+ */
+struct String
+{
+	private char[] data;
+	private size_t length_;
+
+	invariant
+	{
+		assert(length_ <= data.length);
+	}
+
+	/// Ditto.
+	this(const(char)[] str, shared Allocator allocator = defaultAllocator)
+	nothrow @trusted @nogc
+	{
+		this(allocator);
+
+		data = cast(char[]) allocator.allocate(str.length);
+		if (str.length > 0 && data is null)
+		{
+				onOutOfMemoryErrorNoGC();
+		}
+		memcpy(data.ptr, str.ptr, str.length);
+	}
+
+	/// Ditto.
+	this(const(wchar)[] str, shared Allocator allocator = defaultAllocator)
+	nothrow @trusted @nogc
+	{
+		this(allocator);
+
+	}
+
+	/// Ditto.
+	this(const(dchar)[] str, shared Allocator allocator = defaultAllocator)
+	nothrow @trusted @nogc
+	{
+		this(allocator);
+
+	}
+
+	/// Ditto.
+	this(shared Allocator allocator) pure nothrow @safe @nogc
+	in
+	{
+		assert(allocator !is null);
+	}
+	body
+	{
+		allocator_ = allocator;
+	}
+
+	~this() nothrow @trusted @nogc
+	{
+		allocator.deallocate(data);
+	}
+
+	mixin DefaultAllocator;
+}