Features from optional dependencies

openssl implicit feature

Enables openssl

openssl:

OpenSSL bindings

reqwest implicit feature

Enables reqwest ^0.11

reqwest:

higher level HTTP client library

ring implicit feature

Enables ring ^0.16.12

ring:

Safe, fast, small crypto using Rust

rouille implicit feature

Enables rouille

rouille:

High-level idiomatic web framework