type Engine struct {
DefaultNumberOfShards int `mapstructure:"default-number-of-shards" json:"default_number_of_shards" yaml:"default-number-of-shards"`
DefaultBatchSize int `mapstructure:"default-batch-size" json:"default_batch_size" yaml:"default-batch-size"`
DefaultSearchResultSize int `mapstructure:"default-search-result-size" json:"default_search_result_size" yaml:"default-search-result-size"`
}