smithy-http: Disable auto-decompression in aiohttp client (#708)

Author: arandito

packages/smithy-http/.changes/next-release/smithy-http-bugfix-0c383aa7346a4eb4b21cef8e2e0f201a.json

@@ -0,0 +1,4 @@
+{
+  "type": "bugfix",
+  "description": "Disabled automatic response decompression in `AIOHTTPClient`."
+}

packages/smithy-http/src/smithy_http/aio/aiohttp.py

@@ -65,7 +65,13 @@ def __init__(
         """
         _assert_aiohttp()
         self._config = client_config or AIOHTTPClientConfig()
-        self._session = _session or aiohttp.ClientSession()
+        # Disable transparent response decompression and advertise
+        # 'identity' to request uncompressed responses.
+        # TODO: add a functional test once the test client framework exists
+        self._session = _session or aiohttp.ClientSession(
+            auto_decompress=False,
+            headers={"Accept-Encoding": "identity"},
+        )
 
     async def send(
         self,