Cargo Features

futures_codec has no features set by default.

[dependencies]
futures_codec = { version = "0.4.1", features = ["json", "cbor"] }
json = serde, serde_json
cbor = serde, serde_cbor

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.

serde_cbor cbor?
serde_json json?
serde cbor? json?