diff --git a/pkg/rewindablereader/reader.go b/pkg/rewindablereader/reader.go
index c3563e90..52e08c3d 100644
--- a/pkg/rewindablereader/reader.go
+++ b/pkg/rewindablereader/reader.go
@@ -6,25 +6,30 @@ import (
 	"io"
 )
 
-const (
-	maxRecordedSize = 1 * 1024 * 1024
-)
-
 // Reader is a reader that can be (and must be) rewinded once.
 type Reader struct {
-	R io.Reader
+	R       io.Reader
+	MaxSize int
 
-	entries  [][]byte
-	size     int
-	rewinded bool
+	initialized bool
+	entries     [][]byte
+	size        int
+	rewinded    bool
 }
 
 // Read implements io.Reader.
 func (r *Reader) Read(p []byte) (int, error) {
+	if !r.initialized {
+		r.initialized = true
+		if r.MaxSize == 0 {
+			r.MaxSize = 1 * 1024 * 1024
+		}
+	}
+
 	if !r.rewinded {
 		n, err := r.R.Read(p)
 
-		if (r.size + n) > maxRecordedSize {
+		if (r.size + n) > r.MaxSize {
 			return 0, errors.New("max recorded size exceeded")
 		}