Minor fixes and tweaks

Author: mnadareski

BitStream.cs

@@ -2,6 +2,7 @@
 using System.IO;
 using SabreTools.IO;
 
+// TODO: Add more complete implementation to SabreTools.IO
 namespace SabreTools.Compression
 {
     /// <summary>
@@ -18,7 +19,7 @@ public class BitStream
         /// <summary>
         /// Original stream source
         /// </summary>
-        private Stream _source;
+        private readonly Stream _source;
 
         /// <summary>
         /// Last read byte value from the stream

LZ/Decompressor.cs

@@ -57,7 +57,7 @@ public class Decompressor
             long read = lz.CopyTo(sourceState, destState, out LZERROR error);
 
             // Copy the data to the buffer
-            var decompressed = new byte[0];
+            byte[]? decompressed;
             if (read == 0 || (error != LZERROR.LZERROR_OK && error != LZERROR.LZERROR_NOT_LZ))
             {
                 decompressed = null;

MSZIP/DeflateDecompressor.cs

@@ -13,7 +13,7 @@ public class DeflateDecompressor
         /// <summary>
         /// Internal bitstream to use for decompression
         /// </summary>
-        private BitStream _bitStream;
+        private readonly BitStream _bitStream;
 
         /// <summary>
         /// Create a new Decompressor from a byte array