Function rsign::sign

pub fn sign<W>(
    sk_key: SeckeyStruct, 
    pk_key: Option<PubkeyStruct>, 
    sig_buf: W, 
    message: &[u8], 
    hashed: bool, 
    trusted_comment: &str, 
    untrusted_comment: &str
) -> Result<()> where
    W: Write,