diff --git a/protocol/protocol.go b/protocol/protocol.go
index 729a37da..83810de2 100644
--- a/protocol/protocol.go
+++ b/protocol/protocol.go
@@ -9,6 +9,9 @@ type ConnectionID uint64
 // A StreamID in QUIC
 type StreamID uint32
 
+// A ByteCount in QUIC
+type ByteCount uint64
+
 // An ErrorCode in QUIC
 type ErrorCode uint32