diff --git a/elasticapm/transport/base.py b/elasticapm/transport/base.py
index 24911c395..b81960907 100644
--- a/elasticapm/transport/base.py
+++ b/elasticapm/transport/base.py
@@ -250,6 +250,7 @@ def _flush(self, buffer, forced_flush=False) -> None:
         """
         if not self.state.should_try():
             logger.error("dropping flushed data due to transport failure back-off")
+            buffer.close()
         else:
             fileobj = buffer.fileobj  # get a reference to the fileobj before closing the gzip file
             buffer.close()
@@ -261,6 +262,8 @@ def _flush(self, buffer, forced_flush=False) -> None:
             except Exception as e:
                 self.handle_transport_fail(e)
 
+            data.release()
+
     def start_thread(self, pid=None) -> None:
         super(Transport, self).start_thread(pid=pid)
         if (not self._thread or self.pid != self._thread.pid) and not self._closed:
diff --git a/elasticapm/utils/__init__.py b/elasticapm/utils/__init__.py
index 0f7b52c0d..4403f5abd 100644
--- a/elasticapm/utils/__init__.py
+++ b/elasticapm/utils/__init__.py
@@ -78,6 +78,8 @@ def get_name_from_func(func: FunctionType) -> str:
         return "partial({})".format(get_name_from_func(func.func))
     elif hasattr(func, "_partialmethod") and hasattr(func._partialmethod, "func"):
         return "partial({})".format(get_name_from_func(func._partialmethod.func))
+    elif hasattr(func, "__partialmethod__") and hasattr(func.__partialmethod__, "func"):
+        return "partial({})".format(get_name_from_func(func.__partialmethod__.func))
 
     module = func.__module__
 
diff --git a/tests/transports/test_base.py b/tests/transports/test_base.py
index 1aa1a8941..2f77c3e95 100644
--- a/tests/transports/test_base.py
+++ b/tests/transports/test_base.py
@@ -107,18 +107,25 @@ def test_empty_queue_flush(mock_send, elasticapm_client):
         transport.close()
 
 
-@mock.patch("elasticapm.transport.base.Transport.send")
+@mock.patch("elasticapm.transport.base.Transport._flush")
 @pytest.mark.parametrize("elasticapm_client", [{"api_request_time": "5s"}], indirect=True)
-def test_metadata_prepended(mock_send, elasticapm_client):
+def test_metadata_prepended(mock_flush, elasticapm_client):
     transport = Transport(client=elasticapm_client, compress_level=0)
     transport.start_thread()
     transport.queue("error", {}, flush=True)
     transport.close()
-    assert mock_send.call_count == 1
-    args, kwargs = mock_send.call_args
-    data = gzip.decompress(args[0])
+    assert mock_flush.call_count == 1
+    args, kwargs = mock_flush.call_args
+    buffer = args[0]
+    # this test used to mock send but after we fixed a leak for not releasing the memoryview containing
+    # the gzipped data we cannot read it anymore. So reimplement _flush and read the data ourselves
+    fileobj = buffer.fileobj
+    buffer.close()
+    compressed_data = fileobj.getbuffer()
+    data = gzip.decompress(compressed_data)
     data = data.decode("utf-8").split("\n")
     assert "metadata" in data[0]
+    compressed_data.release()
 
 
 @mock.patch("elasticapm.transport.base.Transport.send")