Protobuf trait enforces From<Self>

[rnbguy]

#1456 makes the conversion between tendermint-rs's auto-compiled Google's Duration and core::time::Duration fallible in both direction.

But, the Protobuf trait requires T: From<Self>

tendermint-rs/proto/src/lib.rs

Line 105 in 2f94e7f

pub trait Protobuf<T: Message + From<Self> + Default>

To include the changes for Duration type, this should be refactored to:

 pub trait Protobuf<T: Message + TryFrom<Self> + Default> 

cosmos/ibc-rs#1376 describes a breakage because of this.

[rnbguy]

I explored the idea of the refactor. But it seems that, it makes encode_vec and encode_length methods infallible - which in turn makes hash, sign_bytes and similar methods in domain types infallible.