rust itself:
 * specialization.
 * existential types.
 * async functions in traits (without #[async_trait]).

dalek-crypto:
* Upgrade to latest version of rand crate.

ed25519-dalek:
* defer signature verification without prehash mode.

phf:
* much cheaper hash function

rsa:
* get raw signed data, to allow multiple signed formats.

crypto:
* key agreement trait (Or do they have one already?)

ed25519 trait:
* batch support. (or do they have one already?)

native-tls:
* Support for RFC5705 exporters where available.



# Not actually using these crates:

bitvec
* more efficient bitwise operations.

ring:
* static curve25519

pem:
* should use multiline support or at least not copy when decoding
  base64 multiline.
* should be stricter?

rsa-der:
* Support for RSA key without OID

webpki:
* Support for cert without extensions and/or without alpn

tls-api:
* Async support
* Support for disabling certificate & hostname verification
* Support for getting certificate (or does it have it?)
* Support for RFC5705 exporters