perf(ext/fetch): speed up `resp.clone()` (#24812)

1 files changed, 17 insertions, 4 deletions

diff --git a/ext/fetch/22_body.js b/ext/fetch/22_body.js
index e9d493658..82f41411d 100644
--- a/ext/fetch/22_body.js
+++ b/ext/fetch/22_body.js
@@ -196,10 +196,23 @@ class InnerBody {
    * @returns {InnerBody}
    */
   clone() {
-    const { 0: out1, 1: out2 } = readableStreamTee(this.stream, true);
-    this.streamOrStatic = out1;
-    const second = new InnerBody(out2);
-    second.source = core.deserialize(core.serialize(this.source));
+    let second;
+    if (
+      !ObjectPrototypeIsPrototypeOf(
+        ReadableStreamPrototype,
+        this.streamOrStatic,
+      ) && !this.streamOrStatic.consumed
+    ) {
+      second = new InnerBody({
+        body: this.streamOrStatic.body,
+        consumed: false,
+      });
+    } else {
+      const { 0: out1, 1: out2 } = readableStreamTee(this.stream, true);
+      this.streamOrStatic = out1;
+      second = new InnerBody(out2);
+    }
+    second.source = this.source;
     second.length = this.length;
     return second;
   }