public boolean copy2IoBuffer(final String source, final ByteBufferCollector destBuf, final CopyOptions opt)
                                                                                                               throws InterruptedException {
        final Session session = startCopy2IoBuffer(source, destBuf, opt);
        if (session == null) {
            return false;
        }
        try {
            session.join();
            return session.status().isOk();
        } finally {
            Utils.closeQuietly(session);
        }
    }
Copy `source` from remote to  buffer.
@param source  source from remote
@param destBuf buffer of dest
@param opt     options of copy
@return true if copy success
jraft-core/src/main/java/com/alipay/sofa/jraft/storage/snapshot/remote/RemoteFileCopier.java