diff --git a/source/tanya/async/event/epoll.d b/source/tanya/async/event/epoll.d
index bcc375e..998ad18 100644
--- a/source/tanya/async/event/epoll.d
+++ b/source/tanya/async/event/epoll.d
@@ -34,7 +34,7 @@ extern (C) nothrow @nogc
 	int epoll_wait (int epfd, epoll_event *events, int maxevents, int timeout);
 }
 
-class EpollLoop : SelectorLoop
+final class EpollLoop : SelectorLoop
 {
 	protected int fd;
 	private Vector!epoll_event events;
diff --git a/source/tanya/async/event/iocp.d b/source/tanya/async/event/iocp.d
index 2194304..31e57c8 100644
--- a/source/tanya/async/event/iocp.d
+++ b/source/tanya/async/event/iocp.d
@@ -26,7 +26,7 @@ import core.sys.windows.winbase;
 import core.sys.windows.windef;
 import core.sys.windows.winsock2;
 
-class IOCPStreamTransport : StreamTransport
+final class IOCPStreamTransport : StreamTransport
 {
 	private WriteBuffer!ubyte input;
 
@@ -106,7 +106,7 @@ class IOCPStreamTransport : StreamTransport
 	}
 }
 
-class IOCPLoop : Loop
+final class IOCPLoop : Loop
 {
 	protected HANDLE completionPort;
 
diff --git a/source/tanya/async/event/kqueue.d b/source/tanya/async/event/kqueue.d
index 0e448af..e52a737 100644
--- a/source/tanya/async/event/kqueue.d
+++ b/source/tanya/async/event/kqueue.d
@@ -113,7 +113,7 @@ extern(C) int kevent(int kq, const kevent_t *changelist, int nchanges,
                      kevent_t *eventlist, int nevents, const timespec *timeout)
                      nothrow @nogc;
 
-class KqueueLoop : SelectorLoop
+final class KqueueLoop : SelectorLoop
 {
 	protected int fd;
 	private Vector!kevent_t events;
diff --git a/source/tanya/async/event/selector.d b/source/tanya/async/event/selector.d
index 3aa105c..83a9fce 100644
--- a/source/tanya/async/event/selector.d
+++ b/source/tanya/async/event/selector.d
@@ -25,7 +25,7 @@ import tanya.network.socket;
 /**
  * Transport for stream sockets.
  */
-class SelectorStreamTransport : IOWatcher, StreamTransport
+final class SelectorStreamTransport : IOWatcher, StreamTransport
 {
 	/// Input buffer.
 	package WriteBuffer!ubyte input;
diff --git a/source/tanya/container/string.d b/source/tanya/container/string.d
deleted file mode 100644
index 05f9e70..0000000
--- a/source/tanya/container/string.d
+++ /dev/null
@@ -1,77 +0,0 @@
-/* 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;
-}