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: expression.go
    path of file: ./repos/benthos/internal/bloblang/field
    
    the code of the file until where you have to start completion: package field

import (
	"bytes"

	"github.com/benthosdev/benthos/v4/internal/message"
)

// Message is an interf
    
func (e *Expression) resolve(index int, msg Message, escaped bool) ([]byte, error) {
	if len(e.resolvers) == 1 {
		return e.resolvers[0].ResolveBytes(index, msg, escaped)
	}
	var buf bytes.Buffer
	for _, r := range e.resolvers {
		b, err := r.ResolveBytes(index, msg, escaped)
		if err != nil {
			return nil, err
		}
		_, _ = buf.Write(b)
	}
	return buf.Bytes(), nil
}