iOS开发蓝牙传输文件实时速率只有7kb/s， 型号是ESP32-S3。iOS端传输的文件只有300kb，耗时40秒才完成传输，找不到导致传输文件慢的问题原因，求助大佬们帮忙.这是我的完整代码

[nengqi]

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1. import CoreBluetooth
2. import SwiftUI
3.  
4. struct ContentView: View {
5.   @State private var fileURL: URL? = nil
6.   @State private var status: String = "Not Connected"
7.   @StateObject private var bluetoothManager = BluetoothManager()
8.  
9.   var transferRateText: String {
10.     let transferRateKB = bluetoothManager.transferRate / 1024
11.     if transferRateKB < 1024 {
12.       return String(format: "%.2f KB/s", transferRateKB)
13.     } else {
14.       let transferRateMB = transferRateKB / 1024
15.       return String(format: "%.2f MB/s", transferRateMB)
16.     }
17.   }
18.  
19.   var body: some View {
20.     VStack {
21.       Button("Select File") {
22.         // TODO: Select file
23.         selectFile()
24.       }
25.       .padding()
26.  
27.       Text("Status: \(bluetoothManager.status)")
28.         .padding()
29.       Text("Transfer Rate: \(transferRateText)")
30.         .padding()
31.  
32.       Text("Total Time: \(bluetoothManager.totalTime, specifier: "%.2f") seconds")
33.         .padding()
34.       List(bluetoothManager.discoveredDevices, id: \.identifier) { device in
35.         HStack {
36.           Text(device.name ?? "Unknown")
37.           Spacer()
38.           Button("Connect") {
39.             bluetoothManager.connectToDevice(device)
40.           }
41.         }
42.       }
43.     }
44.   }
45.  
46.   private func selectFile() {
47.     bluetoothManager.presentFilePicker()
48.   }
49. }
50.  
51. #Preview {
52.   ContentView()
53. }
54.  
55. class BluetoothManager: NSObject, ObservableObject, CBCentralManagerDelegate, CBPeripheralDelegate {
56.   private var centralManager: CBCentralManager!
57.   private var peripheral: CBPeripheral?
58.   public var fileTransferCharacteristic: CBCharacteristic?
59.   @Published var status: String = "Not Connected"
60.   @Published var discoveredDevices: [CBPeripheral] = []
61.   private var startTime: Date?
62.   private var endTime: Date?
63.   var fileData: Data!
64.   @Published var transferRate: Double = 0.0
65.   @Published var totalTime: Double = 0.0
66.   private var connectionParameters: [String: Any]?
67.  
68.   override init() {
69.     super.init()
70.     centralManager = CBCentralManager(delegate: self, queue: nil)
71.   }
72.  
73.   func centralManagerDidUpdateState(_ central: CBCentralManager) {
74.     if central.state == .poweredOn {
75.       centralManager.scanForPeripherals(withServices: nil, options: nil)
76.     }
77.   }
78.  
79.   // TODO: Implement other delegate methods
80.  
81.   func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String: Any], rssi RSSI: NSNumber) {
82.     if !discoveredDevices.contains(where: { $0.identifier == peripheral.identifier }) {
83.       discoveredDevices.append(peripheral)
84.     }
85.   }
86.  
87.   func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
88.     print("Connected to peripheral: \(peripheral.name ?? "Unknown")")
89.     status = "Connected to \(peripheral.name ?? "Unknown")"
90.     peripheral.delegate = self
91.     peripheral.discoverServices(nil)
92.   }
93.  
94.   func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) {
95.     if let error = error {
96.       print("Error discovering services: \(error)")
97.       return
98.     }
99.  
100.     for service in peripheral.services ?? [] {
101.       print("Discovered service: \(service.uuid)")
102.       peripheral.discoverCharacteristics(nil, for: service)
103.     }
104.   }
105.  
106.   func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
107.     if let error = error {
108.       print("Error discovering characteristics: \(error)")
109.       return
110.     }
111.  
112.     for characteristic in service.characteristics ?? [] {
113.       print("Discovered characteristic: \(characteristic.uuid)")
114.       if characteristic.uuid == CBUUID(string: "0000ff01-0000-1000-8000-00805f9b34fb") { // Replace with your characteristic UUID
115.         fileTransferCharacteristic = characteristic
116.         // Check MTU size
117.         let mtu = peripheral.maximumWriteValueLength(for: .withResponse)
118.         print("MTU size: \(mtu) bytes")
119.       }
120.     }
121.   }
122.  
123.   public func sendFileData(_ data: Data, to characteristic: CBCharacteristic?) {
124.     guard let characteristic = characteristic else { return }
125.     let mtu = peripheral!.maximumWriteValueLength(for: .withResponse)
126.     var offset = 0
127.  
128.     DispatchQueue.global(qos: .default).async { // Move to a background thread
129.       self.startTime = Date() // Record the start time
130.  
131.       let writeType: CBCharacteristicWriteType = characteristic.properties.contains(.writeWithoutResponse) ? .withoutResponse : .withResponse
132.  
133.       while offset < data.count {
134.         let chunkSize = min(mtu - 3, data.count - offset) // Subtract 3 bytes for BLE header
135.         let chunk = data.subdata(in: offset ..< offset + chunkSize)
136.         self.peripheral?.writeValue(chunk, for: characteristic, type: writeType)
137.         offset += chunkSize
138.         usleep(10000) // 20 millisecond delay
139.       }
140.     }
141.   }
142.  
143.   func peripheral(_ peripheral: CBPeripheral, didWriteValueFor characteristic: CBCharacteristic, error: Error?) {
144.     if let error = error {
145.       print("Error writing value: \(error)")
146.       status = "Error: \(error)"
147.       return
148.     }
149.  
150.     print("Successfully wrote value for characteristic: \(characteristic.uuid)")
151.  
152.     endTime = Date() // Record the end time
153.  
154.     if let startTime = startTime, let endTime = endTime {
155.       let elapsedTime = endTime.timeIntervalSince(startTime)
156.       let fileSize = Double(fileData.count)
157.       let transferRateValue = fileSize / elapsedTime // bytes per second
158.  
159.       print("File transferred successfully")
160.       print("Transfer Rate: \(transferRateValue) B/s")
161.       print("Total Time: \(elapsedTime) seconds")
162.  
163.       // Update the published variables
164.       transferRate = transferRateValue
165.       totalTime = elapsedTime
166.     }
167.   }
168.  
169.   func presentFilePicker() {
170.     let filePicker = UIDocumentPickerViewController(documentTypes: ["public.data"], in: .import)
171.     filePicker.delegate = self
172.     UIApplication.shared.windows.first?.rootViewController?.present(filePicker, animated: true, completion: nil)
173.   }
174.  
175.   func connectToDevice(_ device: CBPeripheral) {
176.     peripheral = device
177.     peripheral?.delegate = self
178.    
179.     let options = [
180.         CBConnectPeripheralOptionNotifyOnConnectionKey: true,
181.         CBConnectPeripheralOptionNotifyOnDisconnectionKey: true,
182.         // Add other options if needed
183.     ]
184.     centralManager.connect(peripheral!, options: options)
185.   }
186. }
187.  
188. extension BluetoothManager: UIDocumentPickerDelegate {
189.   func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
190.     guard let url = urls.first else { return }
191.  
192.     // Create a temporary directory for the file
193.     let tempURL = FileManager.default.temporaryDirectory.appendingPathComponent(url.lastPathComponent)
194.  
195.     do {
196.       // Check if file exists at temporary directory
197.       if FileManager.default.fileExists(atPath: tempURL.path) {
198.         // Remove the file if it exists
199.         try FileManager.default.removeItem(at: tempURL)
200.       }
201.  
202.       // Copy the file to the temporary directory
203.       try FileManager.default.copyItem(at: url, to: tempURL)
204.  
205.       // Read the file data
206. //      let fileData = try Data(contentsOf: tempURL)
207.       fileData = try Data(contentsOf: tempURL)
208.  
209.       // Send the file data
210.       sendFileData(fileData, to: fileTransferCharacteristic)
211.     } catch {
212.       print("Error reading file data: \(error)")
213.       status = "Error: \(error.localizedDescription)"
214.     }
215.   }
216. }
217.  

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[nengqi]

ESP32-S3设置是参考`https://github.com/espressif/esp-idf/tr ... put_server`