various cleanups and comments

src/error.rs

@@ -3,7 +3,7 @@ use std::io::Error as IoError;
 use std::str::Utf8Error;
 use std::string::FromUtf8Error;
 use std::sync::Mutex;
-use std::{fmt, io, mem, result};
+use std::{fmt, io, result};
 
 use actix::MailboxError;
 use cookie;
@@ -22,7 +22,6 @@ pub use url::ParseError as UrlParseError;
 // re-exports
 pub use cookie::ParseError as CookieParseError;
 
-use body::Body;
 use handler::Responder;
 use httprequest::HttpRequest;
 use httpresponse::{HttpResponse, InnerHttpResponse};
@@ -671,16 +670,7 @@ impl<T> InternalError<T> {
     /// Create `InternalError` with predefined `HttpResponse`.
     pub fn from_response(cause: T, response: HttpResponse) -> Self {
         let mut resp = response.into_inner();
-        let body = mem::replace(&mut resp.body, Body::Empty);
-        match body {
-            Body::Empty => (),
-            Body::Binary(mut bin) => {
-                resp.body = Body::Binary(bin.take().into());
-            }
-            Body::Streaming(_) | Body::Actor(_) => {
-                error!("Streaming or Actor body is not support by error response");
-            }
-        }
+        resp.drop_unsupported_body();
 
         InternalError {
             cause,