Returns the number of nanoseconds since the process was started.
This function uses a high-resolution monotonic system timer to provide precise time measurements. In JavaScript, numbers are represented as double-precision floating-point values (IEEE 754), which can safely represent integers up to 2^53 - 1 (Number.MAX_SAFE_INTEGER).
Due to this limitation, while the internal counter may continue beyond this point, the precision of the returned value will degrade after 14.8 weeks of uptime (when the nanosecond count exceeds Number.MAX_SAFE_INTEGER). Beyond this point, the function will continue to count but with reduced precision, which might affect time calculations and comparisons in long-running applications.