public List<byte[]> getChecksums() throws IOException {
        if ( !closed ) {
            throw new IOException("Stream must be closed before getting checksums");
        }
        return Collections.unmodifiableList(checksums);
    }
Returns the list of one-megabyte checksums for this input stream. Only
valid once the stream has been closed.

@throws IOException
            If the stream hasn't been closed.
aws-java-sdk-glacier/src/main/java/com/amazonaws/services/glacier/internal/TreeHashInputStream.java