Error when building excamples

## Bug Report
In building the examples, I got the following error, which stopped me from moving forward.
build.rs:41:10
|
39 | / tonic_build::configure()
40 | | .out_dir(smallbuff_copy)
41 | | .codec_path("crate::common::SmallBufferCodec")
| | -^^^^^^^^^^ method not found in `Builder`
| |_________|
|

For more information about this error, try `rustc --explain E0599`.
error: could not compile `tonic-learn` (build script) due to 1 previous error
warning: build failed, waiting for other jobs to finish...

### Version

blueeye@harry:/mnt/d/11.code/rust/tonic-learn$ cargo tree | grep tonic
tonic-learn v0.1.0 (/mnt/d/11.code/rust/tonic-learn)
├── tonic v0.11.0
├── tonic-health v0.11.0
│ └── tonic v0.11.0 (*)
├── tonic-reflection v0.11.0
│ └── tonic v0.11.0 (*)
├── tonic-types v0.11.0
│ └── tonic v0.11.0 (*)
├── tonic-web v0.11.0
│ ├── tonic v0.11.0 (*)
└── tonic-build v0.11.0

### Platform

WSL-lunix in 64-bit (Windows)

### Crates
tonic-build v0.11.0

### Description