Add support for protocol version 1.21.100 (#12)

internal/pool.go

@@ -0,0 +1,13 @@
+package internal
+
+import (
+	"bytes"
+	"sync"
+)
+
+// BufferPool is a sync.Pool for buffers used to write compressed data to.
+var BufferPool = sync.Pool{
+	New: func() any {
+		return bytes.NewBuffer(make([]byte, 0, 256))
+	},
+}