diff --git a/src/main/php/io/streams/StreamTransfer.class.php b/src/main/php/io/streams/StreamTransfer.class.php
index e323b94b0..61b6106d2 100755
--- a/src/main/php/io/streams/StreamTransfer.class.php
+++ b/src/main/php/io/streams/StreamTransfer.class.php
@@ -19,14 +19,13 @@
  * @test  net.xp_framework.unittest.io.streams.StreamTransferTest
  */
 class StreamTransfer implements Closeable {
-  protected $in= null;
-  protected $out= null;
+  protected $in, $out;
   
   /**
    * Creates a new stream transfer
    *
-   * @param   io.streams.InputStream in
-   * @param   io.streams.OutputStream out
+   * @param  io.streams.InputStream $in
+   * @param  io.streams.OutputStream $out
    */
   public function __construct(InputStream $in, OutputStream $out) {
     $this->in= $in;
@@ -36,22 +35,36 @@ public function __construct(InputStream $in, OutputStream $out) {
   /**
    * Copy all available input from in
    *
-   * @return  int number of bytes copied
-   * @throws  io.IOException
+   * @return int number of bytes copied
+   * @throws io.IOException
    */
   public function transferAll() {
     $r= 0;
-    while ($this->in->available() > 0) {
+    while ($this->in->available()) {
       $r+= $this->out->write($this->in->read());
     }
     return $r;
   }
 
+  /**
+   * Transmit all available input from in, yielding control after each chunk.
+   *
+   * @return iterable
+   * @throws io.IOException
+   */
+  public function transmit() {
+    while ($this->in->available()) {
+      $this->out->write($this->in->read());
+      yield;
+    }
+  }
+
   /**
    * Close input and output streams. Guarantees to try to close both 
    * streams even if one of the close() calls yields an exception.
    *
-   * @throws  io.IOException
+   * @return void
+   * @throws io.IOException
    */
   public function close() {
     $errors= '';
diff --git a/src/test/php/io/unittest/StreamTransferTest.class.php b/src/test/php/io/unittest/StreamTransferTest.class.php
index fe78f58e7..9ad36754e 100755
--- a/src/test/php/io/unittest/StreamTransferTest.class.php
+++ b/src/test/php/io/unittest/StreamTransferTest.class.php
@@ -1,15 +1,12 @@
 <?php namespace io\unittest;
 
+use io\IOException;
 use io\streams\{InputStream, MemoryInputStream, MemoryOutputStream, OutputStream, StreamTransfer};
 use test\{Assert, Test};
 
 class StreamTransferTest {
 
-  /**
-   * Returns an uncloseable input stream
-   *
-   * @return  io.streams.InputStream
-   */
+  /** Returns an uncloseable input stream */
   protected function uncloseableInputStream() {
     return new class() implements InputStream {
       public function read($length= 8192) { }
@@ -18,53 +15,37 @@ public function close() { throw new \io\IOException("Close error"); }
     };
   }
 
-  /**
-   * Returns a closeable input stream
-   *
-   * @return  io.streams.InputStream
-   */
+  /** Returns a closeable input stream */
   protected function closeableInputStream() {
     return new class() implements InputStream {
-      public $closed= FALSE;
+      public $closed= false;
       public function read($length= 8192) { }
       public function available() { }
-      public function close() { $this->closed= TRUE; }
+      public function close() { $this->closed= true; }
     };
   }
   
-  /**
-   * Returns an uncloseable output stream
-   *
-   * @return  io.streams.OutputStream
-   */
+  /** Returns an uncloseable output stream */
   protected function uncloseableOutputStream() {
     return new class() implements OutputStream {
       public function write($data) { }
       public function flush() { }
-      public function close() { throw new \io\IOException("Close error"); }
+      public function close() { throw new IOException('Close error'); }
     };
   }
 
-  /**
-   * Returns a closeable output stream
-   *
-   * @return  io.streams.OutputStream
-   */
+  /** Returns a closeable output stream */
   protected function closeableOutputStream() {
     return new class() implements OutputStream {
-      public $closed= FALSE;
+      public $closed= false;
       public function write($data) { }
       public function flush() { }
-      public function close() { $this->closed= TRUE; }
+      public function close() { $this->closed= true; }
     };
   }
 
-  /**
-   * Test
-   *
-   */
   #[Test]
-  public function dataTransferred() {
+  public function transfer_all() {
     $out= new MemoryOutputStream();
 
     $s= new StreamTransfer(new MemoryInputStream('Hello'), $out);
@@ -73,12 +54,18 @@ public function dataTransferred() {
     Assert::equals('Hello', $out->bytes());
   }
 
-  /**
-   * Test
-   *
-   */
   #[Test]
-  public function nothingAvailableAfterTransfer() {
+  public function transmit() {
+    $out= new MemoryOutputStream();
+
+    $s= new StreamTransfer(new MemoryInputStream('Hello'), $out);
+    foreach ($s->transmit() as $yield) { }
+
+    Assert::equals('Hello', $out->bytes());
+  }
+
+  #[Test]
+  public function nothing_available_after_transfer() {
     $in= new MemoryInputStream('Hello');
 
     $s= new StreamTransfer($in, new MemoryOutputStream());
@@ -87,82 +74,63 @@ public function nothingAvailableAfterTransfer() {
     Assert::equals(0, $in->available());
   }
 
-  /**
-   * Test closing a stream twice has no effect.
-   *
-   * @see   xp://lang.Closeable#close
-   */
   #[Test]
-  public function closingTwice() {
+  public function closing_twice() {
     $s= new StreamTransfer(new MemoryInputStream('Hello'), new MemoryOutputStream());
     $s->close();
     $s->close();
   }
 
-  /**
-   * Test close() method
-   *
-   */
   #[Test]
   public function close() {
     $in= $this->closeableInputStream();
     $out= $this->closeableOutputStream();
+
     (new StreamTransfer($in, $out))->close();
+
     Assert::true($in->closed, 'input closed');
     Assert::true($out->closed, 'output closed');
   }
 
-  /**
-   * Test close() and exceptions
-   *
-   */
   #[Test]
-  public function closingOutputFails() {
+  public function closing_output_fails() {
     $in= $this->closeableInputStream();
     $out= $this->uncloseableOutputStream();
-    
+
     try {
       (new StreamTransfer($in, $out))->close();
       $this->fail('Expected exception not caught', null, 'io.IOException');
-    } catch (\io\IOException $expected) {
+    } catch (IOException $expected) {
       Assert::equals('Could not close output stream: Close error', $expected->getMessage());
     }
     
     Assert::true($in->closed, 'input closed');
   }
 
-  /**
-   * Test close() and exceptions
-   *
-   */
   #[Test]
-  public function closingInputFails() {
+  public function closing_input_fails() {
     $in= $this->uncloseableInputStream();
     $out= $this->closeableOutputStream();
-    
+
     try {
       (new StreamTransfer($in, $out))->close();
       $this->fail('Expected exception not caught', null, 'io.IOException');
-    } catch (\io\IOException $expected) {
+    } catch (IOException $expected) {
       Assert::equals('Could not close input stream: Close error', $expected->getMessage());
     }
 
     Assert::true($out->closed, 'output closed');
   }
 
-  /**
-   * Test close() and exceptions
-   *
-   */
   #[Test]
-  public function closingInputAndOutputFails() {
+  public function closing_input_and_output_fails() {
     $in= $this->uncloseableInputStream();
     $out= $this->uncloseableOutputStream();
-    
+
     try {
       (new StreamTransfer($in, $out))->close();
       $this->fail('Expected exception not caught', null, 'io.IOException');
-    } catch (\io\IOException $expected) {
+    } catch (IOException $expected) {
       Assert::equals('Could not close input stream: Close error, Could not close output stream: Close error', $expected->getMessage());
     }
   }