Cargo Features

[dependencies]
background-jobs-server = { version = "0.4.0", default-features = false, features = ["futures-zmq", "tokio-zmq"] }
default = tokio-zmq

The tokio-zmq feature is set by default whenever background-jobs-server is added without default-features = false somewhere in the dependency tree.

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

futures-zmq implicit feature

Enables futures-zmq ^0.3

futures-zmq:

Provides Futures abstractions for ZeroMQ on any futures executor

tokio-zmq default

Enables tokio-zmq ^0.8