Migrate to fasthttp v1.20.0

Signed-off-by: Evgeniy Kulikov <kim@nspcc.ru>

app.go

@@ -101,13 +101,10 @@ func newApp(ctx context.Context, opt ...Option) App {
 
 	// FIXME don't work with StreamRequestBody,
 	//       some bugs with readMultipartForm
+	// https://github.com/valyala/fasthttp/issues/968
 	// a.web.DisablePreParseMultipartForm = true
 
-	// body streaming
-	// TODO should be replaced in future with
-	//
-	// a.web.StreamRequestBody = v.GetBool(cfgWebStreamRequestBody)
-	checkAndEnableStreaming(a.log, a.cfg, a.web)
+	a.web.StreamRequestBody = a.cfg.GetBool(cfgWebStreamRequestBody)
 	// -- -- -- -- -- -- -- -- -- --
 
 	connections := make(map[string]float64)

settings.go

@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"reflect"
 	"sort"
 	"strconv"
 	"strings"
@@ -13,7 +12,6 @@ import (
 	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
 	"github.com/valyala/fasthttp"
-	"go.uber.org/zap"
 )
 
 type empty int
@@ -90,26 +88,6 @@ var ignore = map[string]struct{}{
 
 func (empty) Read([]byte) (int, error) { return 0, io.EOF }
 
-// checkAndEnableStreaming is temporary shim, should be used before
-// `StreamRequestBody` is not merged in fasthttp master
-// TODO should be removed in future
-func checkAndEnableStreaming(l *zap.Logger, v *viper.Viper, i interface{}) {
-	vi := reflect.ValueOf(i)
-
-	if vi.Type().Kind() != reflect.Ptr {
-		return
-	}
-
-	field := vi.Elem().FieldByName("StreamRequestBody")
-	if !field.IsValid() || field.Kind() != reflect.Bool {
-		l.Warn("stream request body not supported")
-
-		return
-	}
-
-	field.SetBool(v.GetBool(cfgWebStreamRequestBody))
-}
-
 func settings() *viper.Viper {
 	v := viper.New()
 	v.AutomaticEnv()