Cargo Features

[dependencies]
tonic-codec-protobuf = { version = "0.1.0", default-features = false, features = ["protobuf-v3", "protobuf-v2"] }
default = protobuf-v3

The protobuf-v3 feature is set by default whenever tonic-codec-protobuf is added without default-features = false somewhere in the dependency tree.

protobuf-v3 default

Enables protobuf

protobuf-v2

Enables protobuf ^2

tonic-codec-protobuf has 3 features without comments.