tracer.go
func (t Tag) Apply(o *StartSpanOptions) {
	if o.Tags == nil {
		o.Tags = make(map[string]interface{})
	}
	o.Tags[t.Key] = t.Value
}
func (t Tag) Apply(o *StartSpanOptions) {
	if o.Tags == nil {
		o.Tags = make(map[string]interface{})
	}
	o.Tags[t.Key] = t.Value
}
func ( t Tag ) Apply ( o * StartSpanOptions ) { if o . Tags == nil { o . Tags = make ( map [ string ] interface { } ) } o . Tags [ t . Key ] = t . Value }
// Apply satisfies the StartSpanOption interface.
Apply satisfies the StartSpanOption interface .