Fix: corebluetooth write without response

Cargo.toml

@@ -59,6 +59,7 @@ objc2-foundation = { version = "0.2.2", default-features = false, features = [
     "NSString",
     "NSUUID",
     "NSValue",
+    "NSProcessInfo",
 ] }
 objc2-core-bluetooth = { version = "0.2.2", default-features = false, features = [
     "std",

src/corebluetooth/internal.rs

@@ -31,13 +31,14 @@ use objc2_core_bluetooth::{
     CBCharacteristicProperties, CBCharacteristicWriteType, CBDescriptor, CBManager,
     CBManagerAuthorization, CBManagerState, CBPeripheral, CBPeripheralState, CBService, CBUUID,
 };
-use objc2_foundation::{NSArray, NSData, NSMutableDictionary, NSNumber};
+use objc2_foundation::{NSArray, NSData, NSMutableDictionary, NSNumber, NSProcessInfo};
 use std::{
     collections::{BTreeSet, HashMap, VecDeque},
     ffi::CString,
     fmt::{self, Debug, Formatter},
     ops::Deref,
     thread,
+    time::Duration,
 };
 use tokio::runtime;
 use uuid::Uuid;
@@ -368,6 +369,7 @@ impl PeripheralInternal {
 struct CoreBluetoothInternal {
     manager: Retained<CBCentralManager>,
     delegate: Retained<CentralDelegate>,
+    can_send_without_response_supported: bool,
     // Map of identifiers to object pointers
     peripherals: HashMap<Uuid, PeripheralInternal>,
     delegate_receiver: Fuse<Receiver<CentralDelegateEvent>>,
@@ -491,8 +493,16 @@ impl CoreBluetoothInternal {
             msg_send_id![CBCentralManager::alloc(), initWithDelegate: &*delegate, queue: queue]
         };
 
+        let process_info = unsafe { NSProcessInfo::processInfo() };
+        let version = unsafe { process_info.operatingSystemVersion() };
+        let mut can_send_without_response_supported = false;
+        if (version.majorVersion, version.minorVersion) >= (11, 2) {
+            can_send_without_response_supported = true;
+        }
+
         Self {
             manager,
+            can_send_without_response_supported,
             peripherals: HashMap::new(),
             delegate_receiver: receiver.fuse(),
             event_sender,
@@ -887,6 +897,21 @@ impl CoreBluetoothInternal {
                 {
                     trace!("Writing value! With kind {:?}", kind);
                     unsafe {
+                        if kind == WriteType::WithoutResponse
+                            && self.can_send_without_response_supported
+                        {
+                            // probably better idea would be to wait for the result of peripheral.peripheralIsReadyToSendWriteWithoutResponse
+                            let mut attempts = 0;
+                            while !peripheral.peripheral.canSendWriteWithoutResponse()
+                                && attempts < 100
+                            {
+                                attempts += 1;
+                                // min. connection interval time is 15ms. see the document:
+                                // https://developer.apple.com/library/archive/qa/qa1931/_index.html
+                                thread::sleep(Duration::from_millis(15));
+                            }
+                        }
+
                         peripheral.peripheral.writeValue_forCharacteristic_type(
                             &NSData::from_vec(data),
                             &characteristic.characteristic,