Cargo Features

[dependencies]
azure-iot-rs-sys = { version = "0.1.8", default-features = false, features = ["prov_client"] }
default = amqp, http, mqtt, prov_client

These default features are set whenever azure-iot-rs-sys is added without default-features = false somewhere in the dependency tree.

http mqtt amqp prov_client default

azure-iot-rs-sys has 2 features without comments.