Base for 4.3 work. Split Nadeko.Common into a separate project

src/Nadeko.Common/QueueRunner.cs

@@ -0,0 +1,63 @@
+using System.Threading.Channels;
+using Serilog;
+
+namespace Nadeko.Common;
+
+public sealed class QueueRunner
+{
+    private readonly Channel<Func<Task>> _channel;
+    private readonly int _delayMs;
+
+    public QueueRunner(int delayMs = 0, int maxCapacity = -1)
+    {
+        if (delayMs < 0)
+            throw new ArgumentOutOfRangeException(nameof(delayMs));
+
+        _delayMs = delayMs;
+        _channel = maxCapacity switch
+        {
+            0 or < -1 => throw new ArgumentOutOfRangeException(nameof(maxCapacity)),
+            -1 => Channel.CreateUnbounded<Func<Task>>(new UnboundedChannelOptions()
+            {
+                SingleReader = true,
+                SingleWriter = false,
+                AllowSynchronousContinuations = true,
+            }),
+            _ => Channel.CreateBounded<Func<Task>>(new BoundedChannelOptions(maxCapacity)
+            {
+                Capacity = maxCapacity,
+                FullMode = BoundedChannelFullMode.DropOldest,
+                SingleReader = true,
+                SingleWriter = false,
+                AllowSynchronousContinuations = true
+            })
+        };
+    }
+
+    public async Task RunAsync(CancellationToken cancel = default)
+    {
+        while (true)
+        {
+            var func = await _channel.Reader.ReadAsync(cancel);
+            
+            try
+            {
+                await func();
+            }
+            catch (Exception ex)
+            {
+                Log.Warning(ex, "Exception executing a staggered func: {ErrorMessage}", ex.Message);
+            }
+            finally
+            {
+                if (_delayMs != 0)
+                {
+                    await Task.Delay(_delayMs, cancel);
+                }
+            }
+        }
+    }
+    
+    public ValueTask EnqueueAsync(Func<Task> action)
+        => _channel.Writer.WriteAsync(action);
+}