private void separate(boolean useComma) throws IOException {
            boolean newline = ! head || useComma;
            if ( ! head && useComma) {
                out.append((byte)',');
            } else {
                head = false;
            }
            if (indent != null) {
                if (newline) {
                    out.append((byte) '\n');
                    for (int lvl = 0; lvl < level; lvl++) { out.append(indent); }
                } else {
                    out.append((byte) ' ');
                }
            }
        }
Returns the given UTF-8-encoded JSON as a Slime object
vespajlib/src/main/java/com/yahoo/slime/JsonFormat.java