I was rereading that and I will take me time to deeply understand the table.
> Had you read the Wiki, you would know. > “convenient, lightweight and thread-safe callbacks” > https://www.hpi.uni-potsdam.de/hirschfeld/trac/SqueakCommunityProjects/wiki/signals > https://www.hpi.uni-potsdam.de/hirschfeld/trac/SqueakCommunityProjects/wiki/signals#FeatureComparison
