Fix urllib3 proxy instantiation (#763)

diff --git a/httpx/dispatch/urllib3.py b/httpx/dispatch/urllib3.py
index 1782834400ee835d677f1412f363072d19564895..2728170c140b5fa4504fe5419b76731b0880d5cb 100644 (file)
--- a/httpx/dispatch/urllib3.py
+++ b/httpx/dispatch/urllib3.py
@@ -77,7 +77,7 @@ class URLLib3Dispatcher(SyncDispatcher):
             )
         else:
             return urllib3.ProxyManager(
-                proxy_url=proxy.url,
+                proxy_url=str(proxy.url),
                 proxy_headers=dict(proxy.headers),
                 ssl_context=ssl_context,
                 num_pools=num_pools,