Add ADB device tracking (host:track-devices) for real-time device monitoring

[rmarinho]

Summary

Add support for real-time device connection/disconnection monitoring via the ADB daemon socket protocol (\host:track-devices-l).

Changes

• Added \AdbDeviceTracker\ class implementing \IDisposable\
• Socket connection to \localhost:5037\ (ADB daemon)
• Sends \host:track-devices-l\ command and reads length-prefixed device list updates
• Callback-based \StartAsync()\ with \CancellationToken\ support
• \CurrentDevices\ snapshot property for current device state
• Auto-reconnect with exponential backoff (500ms → 16s) on connection drops
• Reuses existing \AdbRunner.ParseAdbDevicesOutput()\ for parsing
• 11 unit tests covering protocol parsing, lifecycle, and edge cases
• Updated \PublicAPI.Unshipped.txt\ for both
  et10.0\ and
  etstandard2.0\

API

\\csharp
public sealed class AdbDeviceTracker : IDisposable
{
public AdbDeviceTracker(string? adbPath = null, int port = 5037, ...);
public IReadOnlyList CurrentDevices { get; }
public Task StartAsync(Action<IReadOnlyList> onDevicesChanged, CancellationToken cancellationToken = default);
public void Dispose();
}
\\

Closes #323

[Copilot]

Pull request overview

Adds a new AdbDeviceTracker public API to Xamarin.Android.Tools.AndroidSdk to monitor ADB device connect/disconnect events in real time using the host:track-devices-l daemon socket protocol.

Changes:

• Introduces AdbDeviceTracker with reconnect/backoff, snapshot state (CurrentDevices), and callback-driven tracking via StartAsync.
• Adds unit tests validating lifecycle guards and length-prefixed protocol parsing behavior.
• Updates PublicAPI unshipped files for netstandard2.0 and net10.0.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
tests/Xamarin.Android.Tools.AndroidSdk-Tests/AdbDeviceTrackerTests.cs	Adds tests for tracker lifecycle and length-prefixed message parsing.
src/Xamarin.Android.Tools.AndroidSdk/Runners/AdbDeviceTracker.cs	Implements TCP-based host:track-devices-l tracking loop with reconnect/backoff and parsing.
src/Xamarin.Android.Tools.AndroidSdk/PublicAPI/netstandard2.0/PublicAPI.Unshipped.txt	Registers the new public API surface for netstandard2.0.
src/Xamarin.Android.Tools.AndroidSdk/PublicAPI/net10.0/PublicAPI.Unshipped.txt	Registers the new public API surface for net10.0.

[Copilot]

using System.Linq; is not used in this file and will trigger CS8019 (and can fail Release builds when warnings are treated as errors). Remove the unnecessary using.

Suggested change

using System.Linq;

[Copilot]

adbPath and environmentVariables are assigned but never used, which will raise CS0414 (and can fail Release builds when warnings are treated as errors). Either implement the advertised behavior (e.g., start/ensure the ADB server using adbPath and pass environmentVariables to that process) or remove these fields/ctor parameters to avoid a misleading public API surface.

[Copilot]

StartAsync creates and stores a linked CancellationTokenSource but never disposes it when StartAsync completes (only on Dispose()), and repeated StartAsync calls will overwrite trackingCts. Consider using a local CTS with a try/finally to dispose it, and guarding against multiple concurrent starts (throw or no-op) to avoid leaks/races.

Suggested change

	trackingCts = CancellationTokenSource.CreateLinkedTokenSource (cancellationToken);
	var token = trackingCts.Token;
	var backoffMs = InitialBackoffMs;
	while (!token.IsCancellationRequested) {
	try {
	await TrackDevicesAsync (onDevicesChanged, token).ConfigureAwait (false);
	} catch (OperationCanceledException) when (token.IsCancellationRequested) {
	break;
	} catch (Exception ex) {
	logger.Invoke (TraceLevel.Warning, $"ADB tracking connection lost: {ex.Message}. Reconnecting in {backoffMs}ms...");
	try {
	await Task.Delay (backoffMs, token).ConfigureAwait (false);
	} catch (OperationCanceledException) {
	break;
	}
	backoffMs = Math.Min (backoffMs * 2, MaxBackoffMs);
	continue;
	}
	// Reset backoff on clean connection
	backoffMs = InitialBackoffMs;
	var linkedCts = CancellationTokenSource.CreateLinkedTokenSource (cancellationToken);
	if (Interlocked.CompareExchange (ref trackingCts, linkedCts, null) != null) {
	linkedCts.Dispose ();
	throw new InvalidOperationException ("Device tracking has already been started.");
	}
	try {
	var token = linkedCts.Token;
	var backoffMs = InitialBackoffMs;
	while (!token.IsCancellationRequested) {
	try {
	await TrackDevicesAsync (onDevicesChanged, token).ConfigureAwait (false);
	} catch (OperationCanceledException) when (token.IsCancellationRequested) {
	break;
	} catch (Exception ex) {
	logger.Invoke (TraceLevel.Warning, $"ADB tracking connection lost: {ex.Message}. Reconnecting in {backoffMs}ms...");
	try {
	await Task.Delay (backoffMs, token).ConfigureAwait (false);
	} catch (OperationCanceledException) {
	break;
	}
	backoffMs = Math.Min (backoffMs * 2, MaxBackoffMs);
	continue;
	}
	// Reset backoff on clean connection
	backoffMs = InitialBackoffMs;
	}
	} finally {
	Interlocked.CompareExchange (ref trackingCts, null, linkedCts);
	linkedCts.Dispose ();