At present we do extensive compression support only in
WF, WPF, ASP.NET WEB and MVC platforms. During the existing compression
process, we have used System.Drawing.Image API for compressing the
existing images. Since System.Drawing.Image API is not available in
XAMARIN and CORE platforms, we are unable to complete our implementation for this feature. Once we find an alternative/equivalent approach, we will provide the support for compressing an existing PDF document.