Tonic doesn't provide tonic::service::LayerExt?

[Gumichocopengin8]

I am trying to use Tonic (tonic = "0.12.3", tonic-web = "0.12.3", tonic-build = "0.12.3") for gRPC-web to call from Reactjs frontend. The Tonic example uses tonic::service::LayerExt

tonic/examples/src/grpc-web/server.rs

Line 1 in 86815d8

use tonic::{service::LayerExt as _, transport::Server, Request, Response, Status};

, but tonic crate doesn't have it. Am I missing something or is the example old and not updated for the latest version?