Prepare for zero-copy sending

mROA.Codegen/MethodRepo.cstmpl

@@ -23,6 +23,7 @@ namespace mROA.Codegen
                 ReturnType = typeof(<!L returnType>),
                 ParameterTypes = new Type[]  { <!L parametersType> },
                 SuitableType = typeof(<!L suitableType>),
+                RequireCancellation = <!L cancellation>,
                 Invoking = (i, parameters, special, post) => <!L funcInvoking>,
             }<!T>
             <!T syncInvoker>