Hello,

I found a bug in ToJSON method. It returns an invalid json because it doesn't escape string fields as expected by json standard specification.
A specific example is:

    var message = new QuickFix.Message();
    message.SetField(new Text("Some text.\r\n With some more text"));

this will produce this json string:

{
    "Header": {},
    "Body": {
        "Text": "Some text.\r\n With some more text"
    },
    "Trailer": {}
}

that is an invalid json. In fact when I try to deserialize it with System.Text.Json it generates a JsonReaderException.