Proposal: msg-sim crate

[mempirate]

Context

Being able to simulate latency, bandwidth, packet loss etc. ("shaping traffic") to reflect the real world is all incredibly useful for testing & benchmarking different protocols. It's how we discovered that QUIC in most cases is actually slower than TCP. We used comcast to add 50ms of latency and a max bandwidth of 1Gbps to localhost, and then ran our benchmarks again.

Proposal

It would be nice to be able to shape traffic in unit tests, integration tests and benchmarks inside of MSG, so I'm proposing the msg-sim crate to do just that. msg-sim will have the following features:

• Support both MacOS and Linux
• Highly configurable
• Standalone crate for use in other projects
• Will be able to do everything comcast can do

Simulation

We usually use localhost for testing, which is the loopback interface. Aside from it being a virtual network interface, it also has a much higher MTU than normal, doesn't use Ethernet etc.