re purpose pr

actix-http/src/message.rs

@@ -387,6 +387,12 @@ impl BoxedResponseHead {
     pub fn new(status: StatusCode) -> Self {
         RESPONSE_POOL.with(|p| p.get_message(status))
     }
+
+    pub(crate) fn take(&mut self) -> Self {
+        BoxedResponseHead {
+            head: self.head.take(),
+        }
+    }
 }
 
 impl std::ops::Deref for BoxedResponseHead {

actix-http/src/response.rs

@@ -1,6 +1,9 @@
 //! Http response
 use std::cell::{Ref, RefMut};
 use std::convert::TryFrom;
+use std::future::Future;
+use std::pin::Pin;
+use std::task::{Context, Poll};
 use std::{fmt, str};
 
 use bytes::{Bytes, BytesMut};
@@ -278,6 +281,18 @@ impl<B: MessageBody> fmt::Debug for Response<B> {
     }
 }
 
+impl Future for Response {
+    type Output = Result<Response, Error>;
+
+    fn poll(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Self::Output> {
+        Poll::Ready(Ok(Response {
+            head: self.head.take(),
+            body: self.body.take_body(),
+            error: self.error.take(),
+        }))
+    }
+}
+
 pub struct CookieIter<'a> {
     iter: header::GetAll<'a>,
 }
@@ -741,6 +756,14 @@ impl<'a> From<&'a ResponseHead> for ResponseBuilder {
     }
 }
 
+impl Future for ResponseBuilder {
+    type Output = Result<Response, Error>;
+
+    fn poll(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Self::Output> {
+        Poll::Ready(Ok(self.finish()))
+    }
+}
+
 impl fmt::Debug for ResponseBuilder {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let head = self.head.as_ref().unwrap();