/// <summary>
/// Creates a new instance with a pattern and an optional validator. The validator will be called before each
/// value is written, and may throw an exception to indicate that the value cannot be serialized.
/// </summary>
/// <param name="pattern">The pattern to use for parsing and formatting.</param>
/// <param name="validator">The validator to call before writing values. May be null, indicating that no validation is required.</param>
/// <exception cref="ArgumentNullException"><paramref name="pattern"/> is null.</exception>
public NodaPatternConverter(IPattern <T> pattern, Action <T> validator)
{
Preconditions.CheckNotNull(pattern, nameof(pattern));
this.pattern = pattern;
this.validator = validator;
}