Adds Status as a strongly-typed property of LibPlcTagException.

src/libplctag.Tests/AsyncTests.cs

@@ -70,7 +70,7 @@ public async Task Timeout_throws_a_LibPlcTagException()
             });
 
             // Assert
-            Assert.Equal(Status.ErrorTimeout.ToString(), ex.Message);
+            Assert.Equal(Status.ErrorTimeout, ex.Status);
         }
 
         [Fact]

src/libplctag.Tests/DisposeTests.cs

@@ -64,7 +64,7 @@ public async Task GithubIssue418()
                 {
                     await tag.InitializeAsync();
                 }
-                catch (Exception e) when (e.Message == "ErrorNotFound") // we are expecting this exception
+                catch (LibPlcTagException e) when (e.Status == Status.ErrorNotFound) // we are expecting this exception
                 {
                 }
             }

src/libplctag/LibPlcTagException.cs

@@ -15,6 +15,8 @@ namespace libplctag
     /// </summary>
     public class LibPlcTagException : Exception
     {
+        public Status Status { get; }
+
         public LibPlcTagException()
         {
         }
@@ -32,6 +34,7 @@ public LibPlcTagException(string message, Exception inner)
         public LibPlcTagException(Status status)
             : base(status.ToString())
         {
+            Status = status;
         }
     }
 }