private TestInputStream createTestInputStream(int testSize) throws IOException {
        return new TestInputStream(
                new BufferedInputStream(Files.newInputStream(createTestFile(testSize))));
    }
Read increasingly more of the stream, but not all, with each pass before rewinding to
make sure we pick up at the correct point
tika-core/src/test/java/org/apache/tika/TestRereadableInputStream.java