public void add(ByteBuf buffer) {
        requireNonNull(buffer, "buffer");
        if (eos.get()) {
            buffer.release();
            throw new IllegalStateException("Already closed");
        }
        if (!buffer.isReadable()) {
            buffer.release();
            return;
        }
        if (!buffers.add(buffer)) {
            buffer.release();
            throw new IllegalStateException("Unable to add new buffer");
        }
    }
Adds new input {@link ByteBuf} data chunk to the {@link InputStream}.
core/src/main/java/com/linecorp/armeria/internal/common/stream/ByteBufsInputStream.java