Potential workaround for poor zstd performance

Performance is still not great, but better

internal/decompress/interface.go

@@ -1,7 +1,19 @@
 package decompress
 
-import "io"
+import (
+	"errors"
+	"io"
+)
+
+var ErrNotResetable = errors.New("decompressor not resetable")
 
 type Decompressor interface {
+	//Creates a new decompressor reading from src.
 	Reader(src io.Reader) (io.ReadCloser, error)
+	//Reports whether Reset will work or not.
+	Resetable() bool
+	//Reset attempts to re-use an old decompressor with new data.
+	//Will return ErrNotResetable if not Resetable().
+	//Must ALWAYS be provided with a reader created with Reader.
+	Reset(old, src io.Reader) error
 }