Cargo Features

mos6502_model has no features set by default.

[dependencies]
mos6502_model = { version = "0.2.1", features = ["serialize"] }
serialize = serde

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 serialize?