Function decode_with_limit 

pub fn decode_with_limit(
    buf: &mut BytesMut,
    max: usize,
) -> Result<Option<BackendMessage>, Error>

Like decode, but rejects any message whose declared body length exceeds max bytes before anything is buffered.

max is clamped to at most i32::MAX (the largest length expressible on the wire).

Errors

Returns Error::Decode when the message is malformed or larger than max.