Imports github.com/gorilla/mux github.com/json-iterator/go github.com/mailgun/mailgun-go/v4/events github.com/pkg/errors Standard library imports bytes context crypto/hmac crypto/rand crypto/sha256 crypto/subtle encoding/hex encoding/json errors fmt io io/ioutil mime/multipart net/http net/http/httptest net/mail net/url os path reflect regexp strconv strings sync time