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: string.go
    path of file: ./repos/fq/format/avro/decoders
    
    the code of the file until where you have to start completion: package decoders

import (
	"github.com/wader/fq/format/avro/schema"
	"github.com/wader/fq/pkg/decode"
	"github.com/wader/fq/pkg/scalar"
)

func decodeStringFn(schema schema.SimplifiedSchema, sms ...scalar.StrMapper) (DecodeFn, error) {
	// String is encoded as a long followed by that many bytes of UTF-8 encoded character data.
	// For example, the three-character string "foo" would be encoded as the long value 3 (encoded as hex 06) followed
	// by the 
    
func decodeStringFn(schema schema.SimplifiedSchema, sms ...scalar.StrMapper) (DecodeFn, error) {
	// String is encoded as a long followed by that many bytes of UTF-8 encoded character data.
	// For example, the three-character string "foo" would be encoded as the long value 3 (encoded as hex 06) followed
	// by the UTF-8 encoding of 'f', 'o', and 'o' (the hex bytes 66 6f 6f):
	// 06 66 6f 6f
	return func(name string, d *decode.D) any {
		var val string
		d.FieldStruct(name, func(d *decode.D) {
			length := d.FieldSintFn("length", VarZigZag)
			val = d.FieldUTF8("data", int(length))
		})
		return val
	}, nil
}