NOTE: 1: http support = whether the libirary/framework handles both websocket/http request, so that they can be seaved from same address/port 2: long polling = either the library/framework handles both long polling/and native websocket. This also includes long polling fallback. 3: Concurrency model = some depends on language, library, or its dependent web server. Disclaimer: I (Makoto Inoue) set u