Merge pull request #1400 from testn/patch-1

Cache lazy-evaluated field

Author: sidorares

lib/packets/column_definition.js

@@ -112,10 +112,19 @@ const addString = function(name) {
     get: function() {
       const start = this[`_${name}Start`];
       const end = start + this[`_${name}Length`];
-      return StringParser.decode(
+      const val = StringParser.decode(
         this._buf.slice(start, end),
         this.encoding === 'binary' ? this._clientEncoding : this.encoding
       );
+      
+      Object.defineProperty(this, name, {
+        value: val,
+        writable: false,
+        configurable: false,
+        enumerable: false
+      });
+
+      return val;
     }
   });
 };