use 'string' instead of '[]byte' for data

1 files changed, 2 insertions, 2 deletions

diff --git a/textproto/io.go b/textproto/io.go
index 9e8f532..1b6402b 100644
--- a/textproto/io.go
+++ b/textproto/io.go
@@ -70,12 +70,12 @@ func (fiw *FIWriter) WriteLine(a ...interface{}) error {
 	return err
 }
 
-func (fiw *FIWriter) WriteData(data []byte) error {
+func (fiw *FIWriter) WriteData(data string) error {
 	err := fiw.WriteLine("data", len(data))
 	if err != nil {
 		return err
 	}
-	_, err = fiw.w.Write(data)
+	_, err = io.WriteString(fiw.w, data)
 	return err
 }