media.go
func (m *MediaService) Get(ctx context.Context, messageSid string, sid string) (*Media, error) {
	me := new(Media)
	err := m.client.GetResource(ctx, mediaPathPart(messageSid), sid, me)
	return me, err
}
func (m *MediaService) Get(ctx context.Context, messageSid string, sid string) (*Media, error) {
	me := new(Media)
	err := m.client.GetResource(ctx, mediaPathPart(messageSid), sid, me)
	return me, err
}
// Get returns a Media struct representing a Media instance, or an error.