Query underlying Stream object for Length, but fallback to original mechanism if the stream doesn't support the Length operation. Addresses drewnoakes#122 by allowing for streamed parsing of metadata.

Author: j4m3z0r

MetadataExtractor/IO/IndexedCapturingReader.cs

@@ -60,9 +60,16 @@ public override long Length
         {
             get
             {
-                IsValidIndex(int.MaxValue, 1);
-                Debug.Assert(_isStreamFinished);
-                return _streamLength;
+                try
+                {
+                    return _stream.Length;
+                }
+                catch (NotSupportedException)
+                {
+                    IsValidIndex(int.MaxValue, 1);
+                    Debug.Assert(_isStreamFinished);
+                    return _streamLength;
+                }
             }
         }