default ByteBuf toByteBuf(HttpData data, int offset, int length) {
        final ByteBuf buf = data.byteBuf(offset, length, ByteBufAccessMode.FOR_IO);
        data.close();
        return buf;
    }
Returns {@code true} if the specified {@code id} and {@code streamId} is writable.
core/src/main/java/com/linecorp/armeria/internal/common/HttpObjectEncoder.java