@Override
    public <K extends FieldValue, V extends FieldValue> void write(FieldBase field, MapFieldValue<K, V> map) {
        buf.putInt1_2_4Bytes(map.size());
        for (Map.Entry<K, V> e : map.entrySet()) {
            e.getKey().serialize(this);
            e.getValue().serialize(this);
        }
    }
Write out the value of array field

@param field - field description (name and data type)
@param array - field value
document/src/main/java/com/yahoo/document/serialization/VespaDocumentSerializer6.java