Use nameof operator instead of string literal.

Duplicati/Library/Main/Options.cs

@@ -1353,7 +1353,7 @@ namespace Duplicati.Library.Main
 
                 long blocksize = Library.Utility.Sizeparser.ParseSize(tmp, "kb");
                 if (blocksize > int.MaxValue || blocksize < 1024)
-                    throw new ArgumentOutOfRangeException("blocksize", string.Format("The blocksize cannot be less than {0}, nor larger than {1}", 1024, int.MaxValue));
+                    throw new ArgumentOutOfRangeException(nameof(blocksize), string.Format("The blocksize cannot be less than {0}, nor larger than {1}", 1024, int.MaxValue));
                 
                 return (int)blocksize;
             }

Duplicati/Library/Utility/DirectStreamLink.cs

@@ -103,7 +103,7 @@ namespace Duplicati.Library.Utility
             m_passWriteThrough = passWriteThrough;
             m_blockOnFlush = blockOnFlush;
             m_blockOnClose = blockOnClose;
-            if (bufsize <= 0) throw new ArgumentOutOfRangeException("bufsize");
+            if (bufsize <= 0) throw new ArgumentOutOfRangeException(nameof(bufsize));
             m_buf = new byte[bufsize];
             m_readerStream = new LinkedReaderStream(this);
             m_writerStream = new LinkedWriterStream(this);