Constant MAX_DIAGNOSTIC_MESSAGE_DECODE_BYTES 

pub const MAX_DIAGNOSTIC_MESSAGE_DECODE_BYTES: usize = _; // 65_536usize

Raw bytes retained for one message while decoding, before sanitization. Every writer sanitizes at construction, so a stored message near this bound was not produced by PowerIO; past it the raw text is truncated, and the result is still sanitized to one bounded line.