Add migrated to .NET 8.0 variant of Hcs.Client

Hcs.ClientNet/GostCryptography/Asn1/Ber/Asn1DerInputStream.cs

@@ -0,0 +1,42 @@
+using System.IO;
+
+namespace GostCryptography.Asn1.Ber
+{
+    public class Asn1DerInputStream : Asn1DerDecodeBuffer, IAsn1InputStream
+    {
+        public Asn1DerInputStream(Stream inputStream)
+            : base(inputStream)
+        {
+        }
+
+        public virtual int Available()
+        {
+            var inputStream = GetInputStream();
+
+            if (inputStream != null)
+            {
+                var num = inputStream.Length - inputStream.Position;
+                return (int)num;
+            }
+
+            return 0;
+        }
+
+        public virtual void Close()
+        {
+            var inputStream = GetInputStream();
+
+            if (inputStream != null)
+            {
+                inputStream.Close();
+            }
+        }
+
+        public virtual bool MarkSupported()
+        {
+            var inputStream = GetInputStream();
+
+            return ((inputStream != null) && inputStream.CanSeek);
+        }
+    }
+}