refactor: optimize file content encoding in NewAttachmentFromFileContent

client/attachment.go

@@ -7,11 +7,12 @@ import (
 )
 
 func NewAttachmentFromFileContent(fileName string, f []byte) (*FileAttachment, error) {
-	base64.StdEncoding.Encode(f, f)
+	buffer := make([]byte, base64.StdEncoding.EncodedLen(len(f)))
+	base64.StdEncoding.Encode(buffer, f)
 
 	return &FileAttachment{
 		Filename: fileName,
-		Content:  string(f),
+		Content:  string(buffer),
 	}, nil
 }