Cargo Features

bigint has no features set by default.

[dependencies]
bigint = { version = "4.4.3", features = ["std", "serialize", "heapsizeof"] }
std heapsizeof? = rustc-hex
serialize = serde, serde_derive
heapsizeof = heapsize, std

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.

rustc-hex std?

Enables rustc-hex ^1.0

heapsize heapsizeof?
serde serialize?
serde_derive serialize?