Function mlb_unescaped 

fn mlb_unescaped<'i>(stream: &mut &'i str) -> &'i str

mlb-unescaped extended with mlb-quotes and LF

warning: newline is not validated

ml-basic-body = *mlb-content *( mlb-quotes 1*mlb-content ) [ mlb-quotes ]

mlb-content = mlb-char / newline / mlb-escaped-nl
mlb-char = mlb-unescaped / escaped
mlb-quotes = 1*2quotation-mark
mlb-unescaped = wschar / %x21 / %x23-5B / %x5D-7E / non-ascii