clean up imports

sanic/response.py

@@ -1,7 +1,5 @@
-import asyncio
 from mimetypes import guess_type
 from os import path
-from inspect import isawaitable
 from ujson import dumps as json_dumps
 
 from aiofiles import open as open_async

sanic/server.py

@@ -21,7 +21,6 @@ except ImportError:
 
 from sanic.log import log
 from sanic.request import Request
-from sanic.response import StreamingHTTPResponse
 from sanic.exceptions import (
     RequestTimeout, PayloadTooLarge, InvalidUsage, ServerError)