Features from optional dependencies

smoelius: https://github.com/rust-lang/cargo/issues/1839 Because of the above issue, the crate for the default format (bincode) must be included regardless of whether it is selected. A test-fuzz test (link) verifies that the crate's code is not linked in when another format is selected.

postcard implicit feature

Enables postcard

postcard:

A no_std + serde compatible message library for Rust