pub const OPTION_INVALID: u16 = u16::MAX; // 65_535u16Expand description
Option value used by this library to indicate a format error in the message that was not detected by the time option / payload processing was started.
As this option is critical and proxy-unsafe, no application can expect to successfully process any message that contains this option. (The number is from the experimental-use range; implementations using this module will simply not support that option in experiments, as they can not distinguish it from an option formatting error).