public override string ToString() {
StringBuilder sb = new StringBuilder("Column(");
sb.Append("Name: ");
sb.Append(Name);
sb.Append(",Value: ");
sb.Append(Value);
sb.Append(",Timestamp: ");
sb.Append(Timestamp);
sb.Append(",Ttl: ");
sb.Append(Ttl);
sb.Append(")");
return sb.ToString();
}