Make InMemoryStream, IteratorStream and methods of Message final

lib/InMemoryStream.php

@@ -8,7 +8,7 @@ use Amp\Success;
 /**
  * Input stream with a single already known data chunk.
  */
-class InMemoryStream implements InputStream {
+final class InMemoryStream implements InputStream {
     private $contents;
 
     /**

lib/IteratorStream.php

@@ -7,7 +7,7 @@ use Amp\Failure;
 use Amp\Iterator;
 use Amp\Promise;
 
-class IteratorStream implements InputStream {
+final class IteratorStream implements InputStream {
     private $iterator;
     private $exception;
 

lib/Message.php

@@ -84,7 +84,7 @@ class Message implements InputStream, Promise {
         return $this->buffer;
     }
 
-    public function read(): Promise {
+    final public function read(): Promise {
         if ($this->pendingRead) {
             throw new PendingReadError;
         }
@@ -117,7 +117,7 @@ class Message implements InputStream, Promise {
     /**
      * {@inheritdoc}
      */
-    public function onResolve(callable $onResolved) {
+    final public function onResolve(callable $onResolved) {
         $this->buffering = true;
 
         if ($this->coroutine === null) {
@@ -141,7 +141,7 @@ class Message implements InputStream, Promise {
      *
      * @return InputStream
      */
-    public function getInputStream(): InputStream {
+    final public function getInputStream(): InputStream {
         return $this->source;
     }
 }