Have one thing i didn't mention above, in thread 25 note about index of line crashed (Utils.swift:46) it's: if contacts[middle].blIdContact < value {

This is block of code illustrate how i call binarySearch(in:for:) : the binarySearch(in:for:) function is not belong to any class and can call directly any where public class ScannerManagerCovid {    func checkContactF() {     let dispatch = DispatchQueue(label: "Bluezone.Trace")     dispatch.async {       let result = BluezoneIdTrace.checkContactF()       resolve(result)     } } class BluezoneIdTrace { static func checkContactF() { let indexfinded = binarySearch(in: contacts, for: bluezoneIdHexString) resolve(indexfinded) } } func binarySearch(in contacts: [Contact], for value: String) -> Int? { ... }