tags

type Extractor interface {
	Extract(reader interface{}) (Tags, error)
}

type Injector interface {
	Inject(tags Tags, carrier interface{}) error
}

type Option func(*options)

type Tags interface {
	// Set sets the given key in the metadata tags.
	Set(key string, value interface{}) Tags
	// Has checks if the given key exists.
	Has(key string) bool
	// Get returns value of given key
	Get(key string) interface{}
	// Values returns a map of key to values.
	// Do not modify the underlying map, please use Set instead.
	Values() map[string]interface{}

	// Foreach some kind like visitor pattern , each element pair will call f func
	//  and if accept return with error , the whole Foreach will return error
	// it some kind like each implementation in ruby https://ruby-doc.org/core-2.7.2/Hash.html#method-i-each
	//todo, require to review the necessary of Foreach to return error
	Foreach(f func(key string, val interface{}) error) error

	Len() int
}