`Result` — Factory and Accessors (v1.39.0)

// Factory
var ok   = Result<Order, ValidationError>.Ok(order);
var fail = Result<Order, ValidationError>.Fail(new ValidationError("Amount required"));

// Accessors
bool succeeded = ok.IsSuccess;    // true
bool failed    = ok.IsFailure;    // false
Order value    = ok.Value;        // throws InvalidOperationException on failure
ValidationError err = fail.Error; // throws InvalidOperationException on success