Added 'connection refused' stream error.

source/mijin/io/stream.hpp

@@ -66,13 +66,14 @@ enum class FileOpenMode
 
 enum class [[nodiscard]] StreamError
 {
-    SUCCESS           = 0,
-    IO_ERROR          = 1,
-    NOT_SUPPORTED     = 2,
-    CONNECTION_CLOSED = 3,
-    PROTOCOL_ERROR    = 4,
-    WOULD_BLOCK       = 5,
-    UNKNOWN_ERROR     = -1
+    SUCCESS            = 0,
+    IO_ERROR           = 1,
+    NOT_SUPPORTED      = 2,
+    CONNECTION_CLOSED  = 3,
+    PROTOCOL_ERROR     = 4,
+    WOULD_BLOCK        = 5,
+    CONNECTION_REFUSED = 6,
+    UNKNOWN_ERROR      = -1
 };
 
 class Stream
@@ -450,6 +451,8 @@ inline const char* errorName(StreamError error) MIJIN_NOEXCEPT
             return "would block";
         case StreamError::UNKNOWN_ERROR:
             return "unknown error";
+        case StreamError::CONNECTION_REFUSED:
+            return "connection refused";
     }
     return "<invalid error>";
 }