feat: execute full-repo remaining parity closure plan

tests/NATS.Server.Tests/IO/AdaptiveReadBufferTests.cs

@@ -0,0 +1,17 @@
+using NATS.Server.IO;
+
+namespace NATS.Server.Tests;
+
+public class AdaptiveReadBufferTests
+{
+    [Fact]
+    public void Read_buffer_scales_between_512_and_65536_based_on_recent_payload_pattern()
+    {
+        var b = new AdaptiveReadBuffer();
+        b.RecordRead(512);
+        b.RecordRead(4096);
+        b.RecordRead(32000);
+        b.CurrentSize.ShouldBeGreaterThan(4096);
+        b.CurrentSize.ShouldBeLessThanOrEqualTo(64 * 1024);
+    }
+}