using System.Runtime;
using System.Runtime.CompilerServices;
var buffers = Make();
Snapshot("allocated");
for (int i = 0; i < buffers.Length; i += 2) buffers[i] = null;
GC.Collect(2, GCCollectionMode.Forced, blocking: true, compacting: false);
Snapshot("after-sweep");
GCSettings.LargeObjectHeapCompactionMode = GCLargeObjectHeapCompactionMode.CompactOnce;
GC.Collect(2, GCCollectionMode.Forced, blocking: true, compacting: true);
Snapshot("after-compact-request");
Console.WriteLine($"kept:{buffers.Count(b => b is not null)}");
GC.KeepAlive(buffers);
[MethodImpl(MethodImplOptions.NoInlining)] static byte[]?[] Make() => Enumerable.Range(0, 24).Select(_ => (byte[]?)new byte[100_000]).ToArray();
static void Snapshot(string label) { var i = GC.GetGCMemoryInfo(); Console.WriteLine($"{label}:index={i.Index};heap={i.HeapSizeBytes};fragmented={i.FragmentedBytes};committed={i.TotalCommittedBytes}"); }