Som small improvements for GPS engine overhaul

InABox.Core/Serialization.cs

@@ -202,6 +202,10 @@ namespace InABox.Core
 
             return stream.ToArray();
         }
+        public static void WriteBinary(this ISerializeBinary obj, Stream stream, BinarySerializationSettings settings)
+        {
+            obj.SerializeBinary(new CoreBinaryWriter(stream, settings));
+        }
 
         public static T ReadBinary<T>(byte[] data, BinarySerializationSettings settings)
             where T : ISerializeBinary, new() => (T)ReadBinary(typeof(T), data, settings);

inabox.digitalmatter/DMRecord.cs

@@ -64,5 +64,8 @@ namespace InABox.DigitalMatter
         {
             return $"[{string.Join(',', _fields.Select(x => x.Dump()))}]";
         }
+
+        public IEnumerable<TField> GetFields<TField>() => 
+            _fields.Where(x => x is TField).Cast<TField>();
     }
 }