added sleep (#3561)

ethdb/privateapi/ethbackend.go

@@ -9,6 +9,7 @@ import (
 	"sort"
 	"sync"
 	"sync/atomic"
+	"time"
 
 	"github.com/holiman/uint256"
 	"github.com/ledgerwatch/erigon-lib/gointerfaces"
@@ -35,6 +36,7 @@ type assemblePayloadPOSFunc func(random common.Hash, suggestedFeeRecipient commo
 var EthBackendAPIVersion = &types2.VersionReply{Major: 3, Minor: 0, Patch: 0}
 
 const MaxPendingPayloads = 128
+const payloadWaitTime = time.Millisecond
 
 type EthBackendServer struct {
 	remote.UnimplementedETHBACKENDServer // must be embedded to have forward compatible implementations.
@@ -269,7 +271,7 @@ func (s *EthBackendServer) EngineNewPayloadV1(ctx context.Context, req *types2.E
 	if header.Hash() != blockHash {
 		return &remote.EnginePayloadStatus{Status: remote.EngineStatus_INVALID_BLOCK_HASH}, nil
 	}
-
+	time.Sleep(payloadWaitTime)
 	// If another payload is already commissioned then we just reply with syncing
 	if atomic.LoadUint32(s.waitingForBeaconChain) == 0 {
 		// We are still syncing a commissioned payload
@@ -340,7 +342,7 @@ func (s *EthBackendServer) EngineForkChoiceUpdatedV1(ctx context.Context, req *r
 	// MUST NOT begin a payload build process if forkchoiceState.headBlockHash doesn't reference a leaf of the block tree
 	// (i.e. it references an old block).
 	// https://github.com/ethereum/execution-apis/blob/v1.0.0-alpha.6/src/engine/specification.md#specification-1
-
+	time.Sleep(payloadWaitTime)
 	if atomic.LoadUint32(s.waitingForBeaconChain) == 0 {
 		return &remote.EngineForkChoiceUpdatedReply{
 			PayloadStatus: &remote.EnginePayloadStatus{Status: remote.EngineStatus_SYNCING},