You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: build.rs
    path of file: ./repos/nix-init/src
    
    the code of the file until where you have to start completion: use std::fmt::{self, Display, Formatter};

use parse_display::Display;

#[derive(Clone, Copy)]
pub enum BuildType {
    BuildGoModule,
    BuildPythonPackage {
        application: bool,
        rust: Option<RustVendor>,
    },
    BuildRustPackage {
        vendor: RustVendor,
    },
    MkDerivation {
        rust: Option<RustVendor>,
    },
}

#[derive(Clone, Copy, Display)]
#[display(style = "camelCase")]
pub enum RustVendor {
    FetchCargoTarball,
    ImportCargoLock,
}

impl Display for BuildType {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        match self {
            BuildType::BuildGoModule => {
    
    
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        match self {
            BuildType::BuildGoModule => {
                write!(f, "buildGoModule")?;
            }

            BuildType::BuildPythonPackage { application, rust } => {
                write!(
                    f,
                    "buildPython{}",
                    if *application {
                        "Application"
                    } else {
                        "Package"
                    },
                )?;
                if let Some(rust) = rust {
                    write!(f, " + {rust}")?;
                }
            }

            BuildType::BuildRustPackage { vendor } => {
                write!(
                    f,
                    "buildRustPackage - {}",
                    match vendor {
                        RustVendor::FetchCargoTarball => "cargoHash",
                        RustVendor::ImportCargoLock => "cargoLock",
                    }
                )?;
            }

            BuildType::MkDerivation { rust } => {
                write!(f, "stdenv.mkDerivation")?;
                if let Some(rust) = rust {
                    write!(f, " + {rust}")?;
                }
            }
        }

        Ok(())
    }