Nanoseconds passed since a server timestamp.
pub fn nsSince(server_timestamp: i64) i64
pub fn nsSince(server_timestamp: i64) i64 {
const ms_passed = js.timestamp() - client_base_timestamp;
const ns_passed = server_base_timestamp - server_timestamp;
return ns_passed + ms_passed * std.time.ns_per_ms;
}