Unable to read MTU: Peripheral does not expose CBPeripheral.maximumWriteValueLength

[Borealin]

When using CoreBluetooth directly, you can obtain the current MTU (i.e. maximum writable data length) via:

let mtu = peripheral.maximumWriteValueLength(for: .withoutResponse)

However, in this library the Peripheral type fully encapsulates the underlying CBPeripheral and does not expose any API for reading its maximumWriteValueLength. Since Swift 6, it’s also no longer safe or supported to use unsafe casts to retrieve the hidden CBPeripheral instance.
Is there a recommended workaround for reading the MTU from the wrapped Peripheral? Are there plans to add native MTU support (i.e. maximumWriteValueLength) to the library’s public API? Thank you!

[meech-ward]

Eventually everything should be added to this library, when I have time.

For now, I've added a new function that should work for these use cases. Let me know if it works for you:

Accessing Underlying CBMPeripheral

The withCBPeripheral method provides safe access to the underlying CBMPeripheral instance:

// Get maximum write length for a peripheral
let maxLength = await peripheral.withCBPeripheral { cbPeripheral in
  cbPeripheral.maximumWriteValueLength(for: .withoutResponse)
}

// Or using shorthand closure syntax
let maxLength = await peripheral.withCBPeripheral {
  $0.maximumWriteValueLength(for: .withoutResponse)
}

// You can also assign to external variables
var writeLength: Int!
await peripheral.withCBPeripheral { cbPeripheral in
  writeLength = cbPeripheral.maximumWriteValueLength(for: .withoutResponse)
}