rpc: fix time key collision for logger with json output (#24112)

The "t" key overrides the log message time in JSON output.

Co-authored-by: Felix Lange <fjl@twurst.com>

rpc/handler.go

@@ -240,7 +240,7 @@ func (h *handler) handleImmediate(msg *jsonrpcMessage) bool {
 		return false
 	case msg.isResponse():
 		h.handleResponse(msg)
-		h.log.Trace("Handled RPC response", "reqid", idForLog{msg.ID}, "t", time.Since(start))
+		h.log.Trace("Handled RPC response", "reqid", idForLog{msg.ID}, "duration", time.Since(start))
 		return true
 	default:
 		return false
@@ -292,12 +292,12 @@ func (h *handler) handleCallMsg(ctx *callProc, msg *jsonrpcMessage) *jsonrpcMess
 	switch {
 	case msg.isNotification():
 		h.handleCall(ctx, msg)
-		h.log.Debug("Served "+msg.Method, "t", time.Since(start))
+		h.log.Debug("Served "+msg.Method, "duration", time.Since(start))
 		return nil
 	case msg.isCall():
 		resp := h.handleCall(ctx, msg)
 		var ctx []interface{}
-		ctx = append(ctx, "reqid", idForLog{msg.ID}, "t", time.Since(start))
+		ctx = append(ctx, "reqid", idForLog{msg.ID}, "duration", time.Since(start))
 		if resp.Error != nil {
 			ctx = append(ctx, "err", resp.Error.Message)
 			if resp.Error.Data != nil {