mbedtls-selftest (cargo): This Rust crate is a support library for the `mbedtls` crate. It contains self-test logic that exports Rust functions and defines C functions. By separating this logic into a separate crate, multiple versions of the `mbedtls` crate can coexist within a single crate. This helps to avoid link name conflict errors. 
Keywords: tls|ssl|cryptography|mbed|mbedtls