diff --git a/netwerk/protocol/http/HttpTransactionChild.cpp b/netwerk/protocol/http/HttpTransactionChild.cpp
index 46765ef57e07..96a6935ed5a0 100644
--- a/netwerk/protocol/http/HttpTransactionChild.cpp
+++ b/netwerk/protocol/http/HttpTransactionChild.cpp
@@ -475,11 +475,14 @@ HttpTransactionChild::OnStopRequest(nsIRequest* aRequest, nsresult aStatus) {
     responseTrailers.emplace(*headerArray);
   }
 
-  Unused << SendOnStopRequest(
-      aStatus, mTransaction->ResponseIsComplete(),
-      mTransaction->GetTransferSize(),
-      ToTimingStructArgs(mTransaction->Timings()), responseTrailers,
-      mTransaction->HasStickyConnection(), mTransactionObserverResult);
+  int64_t requestSize = mTransaction->GetRequestSize();
+
+  Unused << SendOnStopRequest(aStatus, mTransaction->ResponseIsComplete(),
+                              mTransaction->GetTransferSize(),
+                              ToTimingStructArgs(mTransaction->Timings()),
+                              responseTrailers,
+                              mTransaction->HasStickyConnection(),
+                              mTransactionObserverResult, requestSize);
 
   return NS_OK;
 }
diff --git a/netwerk/protocol/http/HttpTransactionParent.cpp b/netwerk/protocol/http/HttpTransactionParent.cpp
index 041ecb804da3..a9c852ca1101 100644
--- a/netwerk/protocol/http/HttpTransactionParent.cpp
+++ b/netwerk/protocol/http/HttpTransactionParent.cpp
@@ -489,7 +489,8 @@ mozilla::ipc::IPCResult HttpTransactionParent::RecvOnStopRequest(
     const int64_t& aTransferSize, const TimingStructArgs& aTimings,
     const Maybe<nsHttpHeaderArray>& aResponseTrailers,
     const bool& aHasStickyConn,
-    Maybe<TransactionObserverResult>&& aTransactionObserverResult) {
+    Maybe<TransactionObserverResult>&& aTransactionObserverResult,
+    const int64_t& aRequestSize) {
   LOG(("HttpTransactionParent::RecvOnStopRequest [this=%p status=%" PRIx32
        "]\n",
        this, static_cast<uint32_t>(aStatus)));
@@ -497,11 +498,12 @@ mozilla::ipc::IPCResult HttpTransactionParent::RecvOnStopRequest(
       this, [self = UnsafePtr<HttpTransactionParent>(this), aStatus,
              aResponseIsComplete, aTransferSize, aTimings, aResponseTrailers,
              aHasStickyConn,
-             aTransactionObserverResult{
-                 std::move(aTransactionObserverResult)}]() mutable {
+             aTransactionObserverResult{std::move(aTransactionObserverResult)},
+             aRequestSize]() mutable {
         self->DoOnStopRequest(aStatus, aResponseIsComplete, aTransferSize,
                               aTimings, aResponseTrailers, aHasStickyConn,
-                              std::move(aTransactionObserverResult));
+                              std::move(aTransactionObserverResult),
+                              aRequestSize);
       }));
   return IPC_OK();
 }
@@ -511,7 +513,8 @@ void HttpTransactionParent::DoOnStopRequest(
     const int64_t& aTransferSize, const TimingStructArgs& aTimings,
     const Maybe<nsHttpHeaderArray>& aResponseTrailers,
     const bool& aHasStickyConn,
-    Maybe<TransactionObserverResult>&& aTransactionObserverResult) {
+    Maybe<TransactionObserverResult>&& aTransactionObserverResult,
+    const int64_t& aRequestSize) {
   LOG(("HttpTransactionParent::DoOnStopRequest [this=%p]\n", this));
   if (mCanceled) {
     return;
@@ -525,6 +528,7 @@ void HttpTransactionParent::DoOnStopRequest(
 
   mResponseIsComplete = aResponseIsComplete;
   mTransferSize = aTransferSize;
+  mRequestSize = aRequestSize;
   TimingStructArgsToTimingsStruct(aTimings, mTimings);
 
   if (aResponseTrailers.isSome()) {
diff --git a/netwerk/protocol/http/HttpTransactionParent.h b/netwerk/protocol/http/HttpTransactionParent.h
index 3de73e2bd2b1..94b417084f36 100644
--- a/netwerk/protocol/http/HttpTransactionParent.h
+++ b/netwerk/protocol/http/HttpTransactionParent.h
@@ -62,7 +62,8 @@ class HttpTransactionParent final : public PHttpTransactionParent,
       const int64_t& aTransferSize, const TimingStructArgs& aTimings,
       const Maybe<nsHttpHeaderArray>& responseTrailers,
       const bool& aHasStickyConn,
-      Maybe<TransactionObserverResult>&& aTransactionObserverResult);
+      Maybe<TransactionObserverResult>&& aTransactionObserverResult,
+      const int64_t& aRequestSize);
   mozilla::ipc::IPCResult RecvOnNetAddrUpdate(const NetAddr& aSelfAddr,
                                               const NetAddr& aPeerAddr,
                                               const bool& aResolvedByTRR);
@@ -100,7 +101,8 @@ class HttpTransactionParent final : public PHttpTransactionParent,
       const int64_t& aTransferSize, const TimingStructArgs& aTimings,
       const Maybe<nsHttpHeaderArray>& responseTrailers,
       const bool& aHasStickyConn,
-      Maybe<TransactionObserverResult>&& aTransactionObserverResult);
+      Maybe<TransactionObserverResult>&& aTransactionObserverResult,
+      const int64_t& aRequestSize);
   void DoNotifyListener();
 
   nsCOMPtr<nsITransportEventSink> mEventsink;
diff --git a/netwerk/protocol/http/PHttpTransaction.ipdl b/netwerk/protocol/http/PHttpTransaction.ipdl
index 9463e51885e8..779295f49ef2 100644
--- a/netwerk/protocol/http/PHttpTransaction.ipdl
+++ b/netwerk/protocol/http/PHttpTransaction.ipdl
@@ -51,7 +51,8 @@ parent:
                       TimingStructArgs timings,
                       nsHttpHeaderArray? responseTrailers,
                       bool hasStickyConn,
-                      TransactionObserverResult? transactionObserverResult);
+                      TransactionObserverResult? transactionObserverResult,
+                      int64_t requestSize);
   async OnNetAddrUpdate(NetAddr selfAddr, NetAddr peerAddr, bool resolvedByTRR);
   async OnInitFailed(nsresult status);
   async OnH2PushStream(uint32_t pushedStreamId,