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: mod.rs
    path of file: ./repos/labrinth/src/auth/email
    
    the code of the file until where you have to start completion: use lettre::message::header::ContentType;
use lettre::message::Mailbox;
use lettre::transport::smtp::authentication::Credentials;
use lettre::{Address, Message, SmtpTransport, Transport};
use thiserror::Error;

#[derive(Error, Debug)]
pub enum MailError {
    #[error("Environment Error")]
    Env(#[from] dotenvy::Error),
    #[error("Mail Error: {0}")]
    Mail(#[from] lettre::error::Error),
    #[error("Address Parse Error: {0}")]
    Address(#[from] lettre::address::AddressError),
    #[error("SMTP Error: {0}")]
    Smtp(#[from] lettre::transport::smtp::Error),
}

pub fn send_email_raw(to: String, subject: String, body: String) -> Result<(), MailE
    
pub fn send_email_raw(to: String, subject: String, body: String) -> Result<(), MailError> {
    let email = Message::builder()
        .from(Mailbox::new(
            Some("Modrinth".to_string()),
            Address::new("no-reply", "mail.modrinth.com")?,
        ))
        .to(to.parse()?)
        .subject(subject)
        .header(ContentType::TEXT_HTML)
        .body(body)?;

    let username = dotenvy::var("SMTP_USERNAME")?;
    let password = dotenvy::var("SMTP_PASSWORD")?;
    let host = dotenvy::var("SMTP_HOST")?;
    let creds = Credentials::new(username, password);

    let mailer = SmtpTransport::relay(&host)?.credentials(creds).build();

    mailer.send(&email)?;

    Ok(())
}