add OutputStream getter

EnvelopeGenerator.PdfEditor/Edit.cs

@@ -7,6 +7,14 @@ using System.Threading.Tasks;
 
 namespace EnvelopeGenerator.PdfEditor
 {
+    public static class Edit
+    {
+        public static Edit<MemoryStream, MemoryStream> FromMemory(byte[] documentBytes)
+        {
+            return new Edit<MemoryStream, MemoryStream>(new MemoryStream(documentBytes), new MemoryStream());
+        }
+    }
+
     public class Edit<TInputStream, TOutputStream> : IDisposable, IAsyncDisposable
         where TInputStream : Stream
         where TOutputStream : Stream
@@ -26,6 +34,26 @@ namespace EnvelopeGenerator.PdfEditor
             _doc = new PdfDocument(_reader, _writer);
         }
 
+        /// <summary>
+        /// Gets the output stream containing the edited PDF document.
+        /// </summary>
+        /// <remarks>
+        /// Accessing this property will close the underlying <see cref="PdfDocument"/> to ensure
+        /// all changes are flushed to the stream. After accessing this property, the PDF document
+        /// can no longer be modified using this <see cref="Edit{TInputStream, TOutputStream}"/> instance.
+        /// </remarks>
+        /// <returns>
+        /// The <typeparamref name="TOutputStream"/> instance that contains the updated PDF bytes.
+        /// </returns>
+        public TOutputStream OutputStream
+        {
+            get
+            {
+                _doc.Close();
+                return _outputStream;
+            }
+        }
+
         public static Edit<MemoryStream, MemoryStream> OnByte(byte[] documentBytes)
         {
             return new Edit<MemoryStream, MemoryStream>(new MemoryStream(documentBytes), new MemoryStream());