Cargo Features

[dependencies]
modbus-core = { version = "0.1.0", default-features = false, features = ["std", "tcp", "rtu"] }
default = rtu, tcp

These default features are set whenever modbus-core is added without default-features = false somewhere in the dependency tree.

std

Enables std of byteorder

tcp default
rtu default

modbus-core has 4 features without comments.