Save extra http Request alloc in webseed request

webseed/client.go

@@ -79,13 +79,13 @@ func (ws *Client) NewRequest(r RequestSpec) Request {
 	var requestParts []requestPart
 	if !ws.fileIndex.Locate(r, func(i int, e segments.Extent) bool {
 		req, err := newRequest(
+			ctx,
 			ws.Url, i, ws.info, e.Start, e.Length,
 			ws.PathEscaper,
 		)
 		if err != nil {
 			panic(err)
 		}
-		req = req.WithContext(ctx)
 		part := requestPart{
 			req:                 req,
 			result:              make(chan requestPartResult, 1),

webseed/request.go

@@ -1,6 +1,7 @@
 package webseed
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 	"net/url"
@@ -46,6 +47,7 @@ func trailingPath(
 
 // Creates a request per BEP 19.
 func newRequest(
+	ctx context.Context,
 	url_ string, fileIndex int,
 	info *metainfo.Info,
 	offset, length int64,
@@ -57,7 +59,7 @@ func newRequest(
 		// for things like spaces and '#'.
 		url_ += trailingPath(info.Name, fileInfo.Path, pathEscaper)
 	}
-	req, err := http.NewRequest(http.MethodGet, url_, nil)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url_, nil)
 	if err != nil {
 		return nil, err
 	}