email/email/message/add/
config.rs

1#[derive(Clone, Debug, Default, Eq, PartialEq)]
2#[cfg_attr(
3    feature = "derive",
4    derive(serde::Serialize, serde::Deserialize),
5    serde(rename_all = "kebab-case")
6)]
7pub struct MessageWriteConfig {
8    /// Define visible headers at the top of messages when writing
9    /// them (new/reply/forward).
10    pub headers: Option<Vec<String>>,
11}