func MergeCountOptions(opts ...*CountOptions) *CountOptions {
	countOpts := Count()
	for _, co := range opts {
		if co == nil {
			continue
		}
		if co.Collation != nil {
			countOpts.Collation = co.Collation
		}
		if co.Hint != nil {
			countOpts.Hint = co.Hint
		}
		if co.Limit != nil {
			countOpts.Limit = co.Limit
		}
		if co.MaxTime != nil {
			countOpts.MaxTime = co.MaxTime
		}
		if co.Skip != nil {
			countOpts.Skip = co.Skip
		}
	}
	return countOpts
}
MergeCountOptions combines the given CountOptions instances into a single CountOptions in a last-one-wins fashion.
package options
import "time"
type CountOptions struct {
	Collation *Collation
	Hint interface{}
	Limit *int64
	MaxTime *time.Duration
	Skip *int64
}
func Count() *CountOptions {
	return &CountOptions{}
}
func (co *CountOptions) SetCollation(c *Collation) *CountOptions {
	co.Collation = c
	return co
}
func (co *CountOptions) SetHint(h interface{}) *CountOptions {
	co.Hint = h
	return co
}
func (co *CountOptions) SetLimit(i int64) *CountOptions {
	co.Limit = &i
	return co
}
func (co *CountOptions) SetMaxTime(d time.Duration) *CountOptions {
	co.MaxTime = &d
	return co
}
func (co *CountOptions) SetSkip(i int64) *CountOptions {
	co.Skip = &i
	return co
}