How can I store longer strings in Xamarin with SQLite.NET

I need to store some larger string blobs in my Xamarin project for caching until it is able to be synced with the server. However it seems that no matter what I try, I am not able to store anything larger than 140 characters.

I tried:

[MaxLength(6000)]
public string Message { get; set; }

but I am still seeing string concatenation.

(This particular one is trying to store stack traces during exception handling, 6000 was just an example length)