Cargo Features

serde_header has no features set by default.

serde_header = { version = "0.2.0", features = ["crate_http"] }
crate_http = http

Affects serde_header::from_header_map

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.

http crate_http?

Enables http ^0.2.1

used in feature http.