simplified logic when handling the body

sanic/response.py

@@ -196,11 +196,13 @@ class HTTPResponse(BaseHTTPResponse):
         if keep_alive and keep_alive_timeout is not None:
             timeout_header = b'Keep-Alive: %d\r\n' % keep_alive_timeout
 
+        body = b''
         content_length = 0
         if self.status is not 204:
+            body = self.body
             content_length = self.headers.get('Content-Length', len(self.body))
-        self.headers['Content-Length'] = content_length
 
+        self.headers['Content-Length'] = content_length
         self.headers['Content-Type'] = self.headers.get(
             'Content-Type', self.content_type)
 
@@ -222,7 +224,7 @@ class HTTPResponse(BaseHTTPResponse):
                    b'keep-alive' if keep_alive else b'close',
                    timeout_header,
                    headers,
-                   self.body if self.status is not 204 else b''
+                   body
                )
 
     @property