Implementing prost::Name for common Components.

[RylanYancey]

I am trying to implement a protocol for synchronizing entity state. I would like to do this by registering Components as "sendable". However, I need a way to uniquely identify a components such that it can be recognized across machines.

Components wouldn't have to implement prost::Message, just prost::Name.

#[cfg(feature = "prost_names")]
impl prost::Name for Transform {
    const NAME: &'static str = "Transform";
    const PACKAGE: &'static str = "bevy.ecs";
}

Then, instead of passing around the entire component name, I could pass around an XXH64 hash of the name, saving space and lookup time.

#[derive(prost::Message)]
pub struct SyncUpdate {
    #[prost(uint64, tag=1)]
    entity: u64,
    #[prost(uint64, tag=2)]
    tick: u64,
    #[prost(uint64, tag=3)]
    name_hash: u64,  // << hash used to identify component
    #[prost(bytes, tag=4)]
    payload: Vec<u8>,
}

[RylanYancey]

Closed because Bevy Reflect does this.