diff --git a/mixpanel/__init__.py b/mixpanel/__init__.py
index d93a1cb..4786434 100644
--- a/mixpanel/__init__.py
+++ b/mixpanel/__init__.py
@@ -567,13 +567,10 @@ def __init__(self, events_url=None, people_url=None, import_url=None,
             "status_forcelist": set(range(500, 600)),
             methods_arg: {"POST"},
         }
-        adapter = requests.adapters.HTTPAdapter(
+        self._adapter = requests.adapters.HTTPAdapter(
             max_retries=urllib3.Retry(**retry_args),
         )
 
-        self._session = requests.Session()
-        self._session.mount('http', adapter)
-
     def send(self, endpoint, json_message, api_key=None, api_secret=None):
         """Immediately record an event or a profile update.
 
@@ -611,8 +608,11 @@ def _write_request(self, request_url, json_message, api_key=None, api_secret=Non
         if api_secret is not None:
             basic_auth = HTTPBasicAuth(api_secret, '')
 
+        session = requests.Session()
+        session.mount('http', self._adapter)
+
         try:
-            response = self._session.post(
+            response = session.post(
                 request_url,
                 data=params,
                 auth=basic_auth,