Add stop capture method.

src/NTwain/TwainSession.cs

@@ -367,6 +367,17 @@ namespace NTwain
             return _twain.DatUserinterface(DG.CONTROL, MSG.ENABLEDS, ref ui);
         }
 
+        /// <summary>
+        /// Stops the data source's automated feeder
+        /// if <see cref="Capabilities.CAP_AUTOSCAN"/> is set to true.
+        /// </summary>
+        /// <returns></returns>
+        public STS StopCapture()
+        {
+            TW_PENDINGXFERS pending = default;
+            return _twain.DatPendingxfers(DG.CONTROL, MSG.STOPFEEDER, ref pending);
+        }
+
         /// <summary>
         /// Reads information relating to the last capture run.
         /// Only valid on state 4 after a capture.