With Meteor, we have DDP, so why do we need another RPC?

An open source Remote Procedure Call framework, gRPC uses HTTP/2 for the transport layer initially developed by Google based on their internal RPC framework.The transport layer is one of the key components in gRPC. HTTP/2 is the major upgrade of HTTP/1.1, and it was standardized by the Internet Engineering Steering Group (IESG) in 2015. Every technology that is standardized on the web tends to survive for many years because we, the developers, all accept and agree with that standard primarily because the technology is not owned by a single company that decides its future. JavaScript is a great example of that.On the other hand, Meteor's DDP (Distributed Data Protocol) uses WebSockets for transport format; the WebSockets protocol did not get standardized, which is one important consideration that may drive its future.The second component of gRPC is the data format. The current industry standard is JSON over HTTP, DDP is...