fn header(headers: &HeaderMap, key: &str) -> String {
    headers.get(key)
        .map(|header| header.to_str().unwrap().to_string())
        // If the header is not found, return an empty string
        .unwrap_or_else(|| "".to_string())
}
/// Returns the value of the header specified by the parameter `key`.
Returns the value of the header specified by the parameter `key`.
Returns the value of the header specified by the parameter ` key ` .
fn header(headers: &HeaderMap, key: &str) -> String {
    headers.get(key)
        .map(|header| header.to_str().unwrap().to_string())
        // If the header is not found, return an empty string
        .unwrap_or_else(|| "".to_string())
}
fn header ( headers : & HeaderMap , key : & str ) -> String { headers . get ( key ) . map ( | header | header . to_str ( ) . unwrap ( ) . to_string ( ) ) // If the header is not found, return an empty string . unwrap_or_else ( | | " " . to_string ( ) ) }
Returns the value of the header specified by the parameter `key`.
Returns the value of the header specified by the parameter ` key ` .
headers
&HeaderMap
key
&str
headers
&HeaderMap
key
&str