Function jws::get_header_param

pub fn get_header_param<'a>(
    protected: Option<&'a JsonObject>, 
    unprotected: Option<&'a JsonObject>, 
    key: &str
) -> Option<&'a JsonValue>

Get a parameter from either the protected or unprotected header, depending on which are available and which has the parameter.

If a parameter is found in the protected header, the unprotected header is not consulted anymore.