Added networkedvar string null safeguards

Author: TwoTenPvP

MLAPI/Data/NetworkedVar.cs

@@ -216,9 +216,9 @@ public string GetChannel()
     public class NetworkedVarString : NetworkedVar<string>
     {
         /// <inheritdoc />
-        public NetworkedVarString() { }
+        public NetworkedVarString() : base(string.Empty) { }
         /// <inheritdoc />
-        public NetworkedVarString(NetworkedVarSettings settings) : base(settings) { }
+        public NetworkedVarString(NetworkedVarSettings settings) : base(settings, string.Empty) { }
         /// <inheritdoc />
         public NetworkedVarString(string value) : base(value) { }
         /// <inheritdoc />

MLAPI/NetworkingManagerComponents/Binary/BitWriter.cs

@@ -97,6 +97,10 @@ public void WriteObjectPacked(object value)
             }
             else if (value is string)
             {
+                if (value == null)
+                {
+                    throw new ArgumentException("BitWriter cannot write strings with a null value");
+                }
                 WriteStringPacked((string)value);
                 return;
             }
@@ -186,8 +190,12 @@ public void WriteObjectPacked(object value)
                 WriteUInt16Packed(((NetworkedBehaviour)value).GetBehaviourId());
                 return;
             } 
-            else if(value is IBitWritable)
+            else if (value is IBitWritable)
             {
+                if (value == null)
+                {
+                    throw new ArgumentException("BitWriter cannot write IBitWritable types with a null value");
+                }
                 ((IBitWritable)value).Write(this.sink);
                 return;
             }