diff --git a/src/Compressor.php b/src/Compressor.php
index 7ced4d7..faa3150 100644
--- a/src/Compressor.php
+++ b/src/Compressor.php
@@ -34,11 +34,15 @@ final class Compressor extends TransformStream
     /** @var ?resource */
     private $context;
 
+    /** @var int */
+    private $flush;
+
     /**
      * @param int $encoding ZLIB_ENCODING_GZIP, ZLIB_ENCODING_RAW or ZLIB_ENCODING_DEFLATE
      * @param int $level    optional compression level
+     * @param int $flush    optional flush mode (ZLIB_NO_FLUSH, ZLIB_SYNC_FLUSH, ZLIB_FULL_FLUSH, ZLIB_FINISH)
      */
-    public function __construct($encoding, $level = -1)
+    public function __construct($encoding, $level = -1, int $flush = ZLIB_NO_FLUSH)
     {
         $errstr = '';
         set_error_handler(function ($_, $error) use (&$errstr) {
@@ -61,12 +65,17 @@ public function __construct($encoding, $level = -1)
             throw new \InvalidArgumentException('Unable to initialize compressor' . $errstr); // @codeCoverageIgnore
         }
 
+        if (!in_array($flush, [ZLIB_NO_FLUSH, ZLIB_SYNC_FLUSH, ZLIB_FULL_FLUSH, ZLIB_FINISH], true)) {
+            throw new \InvalidArgumentException('Argument #3 ($flush) must be one of ZLIB_NO_FLUSH, ZLIB_SYNC_FLUSH, ZLIB_FULL_FLUSH or ZLIB_FINISH');
+        }
+
         $this->context = $context;
+        $this->flush = $flush;
     }
 
     protected function transformData($chunk)
     {
-        $ret = deflate_add($this->context, $chunk, ZLIB_NO_FLUSH);
+        $ret = deflate_add($this->context, $chunk, $this->flush);
 
         if ($ret !== '') {
             $this->emit('data', [$ret]);
diff --git a/tests/CompressorTest.php b/tests/CompressorTest.php
index 5eaf037..000942c 100644
--- a/tests/CompressorTest.php
+++ b/tests/CompressorTest.php
@@ -30,4 +30,10 @@ public function testCtorThrowsForInvalidEncodingAndUnsetsUsedErrorHandler()
 
         $this->assertEquals($handler, $checkHandler);
     }
+
+    public function testCtorThrowsForInvalidFlushMode()
+    {
+        $this->expectException(\InvalidArgumentException::class);
+        new Compressor(ZLIB_ENCODING_GZIP, -1, -1);
+    }
 }
diff --git a/tests/GzipCompressorTest.php b/tests/GzipCompressorTest.php
index 9a6c78c..43646e4 100644
--- a/tests/GzipCompressorTest.php
+++ b/tests/GzipCompressorTest.php
@@ -8,22 +8,21 @@ class GzipCompressorTest extends TestCase
 {
     private $compressor;
 
+    /** @var string */
+    private $os;
+
     /**
      * @before
      */
     public function setUpCompressor()
     {
         $this->compressor = new Compressor(ZLIB_ENCODING_GZIP);
+        $this->os = DIRECTORY_SEPARATOR !== '\\' ? "\x03" : (PHP_VERSION_ID >= 70200 ? "\x0a" : "\x0b"); // UNIX (0x03) or incorrect TOPS-20(0x0a) or NTFS(0x0b)
     }
 
     public function testCompressEmpty()
     {
-        if (DIRECTORY_SEPARATOR === '\\') {
-            $this->markTestSkipped('Not supported on Windows');
-        }
-
-        $os = DIRECTORY_SEPARATOR === '\\' ? "\x0a" : "\x03"; // NTFS(0x0a) or UNIX (0x03)
-        $this->compressor->on('data', $this->expectCallableOnceWith("\x1f\x8b\x08\x00\x00\x00\x00\x00\x00" . $os . "\x03\x00" . "\x00\x00\x00\x00\x00\x00\x00\x00"));
+        $this->compressor->on('data', $this->expectCallableOnceWith("\x1f\x8b\x08\x00\x00\x00\x00\x00\x00" . $this->os . "\x03\x00" . "\x00\x00\x00\x00\x00\x00\x00\x00"));
         $this->compressor->on('end', $this->expectCallableOnce());
 
         $this->compressor->end();
@@ -58,4 +57,41 @@ public function testCompressBig()
         // PHP < 5.4 does not support gzdecode(), so let's assert this the other way around…
         $this->assertEquals(gzencode($data), $buffered);
     }
+
+    public function testWriteWillOnlyFlushHeaderByDefaultToBufferDataBeforeFlushing()
+    {
+        $compressor = new Compressor(ZLIB_ENCODING_GZIP);
+
+        $compressor->on('data', $this->expectCallableOnceWith("\x1f\x8b\x08\x00\x00\x00\x00\x00\x00" . $this->os));
+
+        $compressor->write('hello');
+    }
+
+    public function testWriteWithSyncFlushWillFlushHeaderWithFirstChunkImmediately()
+    {
+        $compressor = new Compressor(ZLIB_ENCODING_GZIP, -1, ZLIB_SYNC_FLUSH);
+
+        $compressor->on('data', $this->expectCallableOnceWith("\x1f\x8b\x08\x00\x00\x00\x00\x00\x00" . $this->os . "\xca\x48\xcd\xc9\xc9\x07\x00\x00\x00\xff\xff"));
+
+        $compressor->write('hello');
+    }
+
+    public function testWriteWithFinishFlushWillFlushEntireGzipHeaderAndFooterWithFirstChunkImmediately()
+    {
+        $compressor = new Compressor(ZLIB_ENCODING_GZIP, -1, ZLIB_FINISH);
+
+        $compressor->on('data', $this->expectCallableOnceWith("\x1f\x8b\x08\x00\x00\x00\x00\x00\x00" . $this->os . "\xcb\x48\xcd\xc9\xc9\x07\x00\x86\xa6\x10\x36" . "\x05\x00\x00\x00"));
+
+        $compressor->write('hello');
+    }
+
+    public function testWriteAfterFinishFlushWillFlushEntireGzipWithSyncFlushWillFlushEntireGzipHeaderAndFooterAgainImmediately()
+    {
+        $compressor = new Compressor(ZLIB_ENCODING_GZIP, -1, ZLIB_FINISH);
+        $compressor->write('hello');
+
+        $compressor->on('data', $this->expectCallableOnceWith("\x1f\x8b\x08\x00\x00\x00\x00\x00\x00" . $this->os . "\xcb\x48\xcd\xc9\xc9\x07\x00\x86\xa6\x10\x36" . "\x05\x00\x00\x00"));
+
+        $compressor->write('hello');
+    }
 }