func NewSearchRequest() *SearchRequest {
	return &SearchRequest{}
}
NewSearchRequest creates a new search request.
package elastic
import "strings"
type SearchRequest struct {
	searchType        string  
	indices           []string
	types             []string
	routing           *string
	preference        *string
	requestCache      *bool
	ignoreUnavailable *bool
	allowNoIndices    *bool
	expandWildcards   string
	scroll            string
	source            interface{}
}