ペイロード全体をメモリにロードせずに JSON ストリームを効率的にデコードするにはどうすればよいですか?

package main

import (
    "bufio"
    "encoding/json"
    "fmt"
    "io"
    "log"
    "os"
)

// Helper error handler
func he(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

// Large object struct
type LargeObject struct {
    Id   string `json:"id"`
    Data string `json:"data"`
}

func main() {
    // JSON input for demonstration
    in := `{"somefield": "value", "otherfield": "othervalue", "items": [ {"id": "1", "data": "data1"}, {"id": "2", "data": "data2"}, {"id": "3", "data": "data3"}, {"id": "4", "data": "data4"}]}`

    dec := json.NewDecoder(strings.NewReader(in))

    // Expect an object
    t, err := dec.Token()
    he(err)
    if delim, ok := t.(json.Delim); !ok || delim != '{' {
        log.Fatal("Expected object")
    }

    // Read props
    for dec.More() {
        t, err = dec.Token()
        he(err)
        prop := t.(string)
        if t != "items" {
            var v interface{}
            he(dec.Decode(&v))
            fmt.Printf("Property '%s' = %v\n", prop, v)
            continue
        }

        // It's the "items". Expect an array
        t, err = dec.Token()
        he(err)
        if delim, ok := t.(json.Delim); !ok || delim != '[' {
            log.Fatal("Expected array")
        }
        // Read items (large objects)
        for dec.More() {
            // Read next item (large object)
            lo := LargeObject{}
            he(dec.Decode(&lo))
            fmt.Printf("Item: %+v\n", lo)
        }
        // Array closing delim
        t, err = dec.Token()
        he(err)
        if delim, ok := t.(json.Delim); !ok || delim != ']' {
            log.Fatal("Expected array closing")
        }
    }

    // Object closing delim
    t, err = dec.Token()
    he(err)
    if delim, ok := t.(json.Delim); !ok || delim != '}' {
        log.Fatal("Expected object closing")
    }
}

Property 'somefield' = value
Property 'otherfield' = othervalue
Item: {Id:1 Data:data1}
Item: {Id:2 Data:data2}
Item: {Id:3 Data:data3}
Item: {Id:4 Data:data4}