Cargo Features

stream-tls-client_hello-detector = { version = "0.2.0", default-features = false, features = ["std_io", "futures_util_io"] }
default = std_io

The std_io feature is set by default whenever stream-tls-client_hello-detector is added without default-features = false somewhere in the dependency tree.

std_io default = std-io-peek
futures_util_io = futures-util-io-peek

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.

std-io-peek std_io
futures-util-io-peek futures_util_io?