Function parse_duration_nsec 

pub fn parse_duration_nsec(s: &str) -> Result<u32, XmlError>

Nanoseconds value for Duration_t.nanosec per Spec §7.2.2 + the nonNegativeInteger_Duration_NSEC pattern.

Accepts:

• Decimal 0..=999_999_999 (regular sub-second range).
• Symbols DURATION_INFINITY and DURATION_INFINITE_NSEC -> sentinel DURATION_INFINITE_NSEC.

Errors

XmlError::ValueOutOfRange on a value > 999_999_999 (unless it is a sentinel).