Is There a Decentralized Messaging Network?

Blockchain is currently only accessible on a public Internet through RPC or basically request response. So it is very inconvenient for the applications because the blockchains and applications are not in one messaging network. What we imagining is a network more similar to a PubSub like a decentralized messaging network where you install an SDK into an app and then you immediately can send messages to other block chains. You can get events from other applications. You can immediately share data between applications because you just encrypt data, send it out through the network.