You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: tracers.go
    path of file: ./repos/lotus/chain/stmgr
    
    the code of the file until where you have to start completion: package stmgr

import (
	"context"

	"github.com/ipfs/go-cid"

	"github.com/filecoin-project/lotus/api"
	"github.com/filecoin-project/lotus/chain/types"
	"github.com/filecoin-project/lotus/
    
func (m *messageFinder) MessageApplied(ctx context.Context, ts *types.TipSet, mcid cid.Cid, msg *types.Message, ret *vm.ApplyRet, implicit bool) error {
	if m.mcid == mcid {
		m.outm = msg
		m.outr = ret
		return errHaltExecution // message was found, no need to continue
	}
	return nil
}