diff --git a/libs/rs/rsContext.cpp b/libs/rs/rsContext.cpp
index dfdeb98..2a94651 100644
--- a/libs/rs/rsContext.cpp
+++ b/libs/rs/rsContext.cpp
@@ -798,7 +798,7 @@
         return false;
     }
     if (!waitForSpace) {
-        if (mIO.mToClient.getFreeSpace() < len) {
+        if (mIO.mToClient.getFreeSpace() <= (len + 8)) {
             // Not enough room, and not waiting.
             return false;
         }