Always process HTTP headers before processing HTTP body. (#95) (#103)

Signed-off-by: Piotr Sikora <piotrsikora@google.com>

Author: PiotrSikora

src/context.cc

@@ -629,6 +629,12 @@ FilterHeadersStatus ContextBase::convertVmCallResultToFilterHeadersStatus(uint64
       result > static_cast<uint64_t>(FilterHeadersStatus::StopAllIterationAndWatermark)) {
     return FilterHeadersStatus::StopAllIterationAndWatermark;
   }
+  if (result == static_cast<uint64_t>(FilterHeadersStatus::StopIteration)) {
+    // Always convert StopIteration (pause processing headers, but continue processing body)
+    // to StopAllIterationAndWatermark (pause all processing), since the former breaks all
+    // assumptions about HTTP processing.
+    return FilterHeadersStatus::StopAllIterationAndWatermark;
+  }
   return static_cast<FilterHeadersStatus>(result);
 }