constructor(validationErrors, results, rawResult, operation) {
    let preview = validationErrors.map(e => e.message).join(', ');
    if (preview.length > 200) {
      preview = preview.slice(0, 200) + '...';
    }
    super(`${operation} failed with ${validationErrors.length} Mongoose validation errors: ${preview}`);

    this.validationErrors = validationErrors;
    this.results = results;
    this.rawResult = rawResult;
    this.operation = operation;
  }
If `bulkWrite()` or `insertMany()` has validation errors, but
all valid operations succeed, and 'throwOnValidationError' is true,
Mongoose will throw this error.

@api private