@Test
    void testEngineDigestWithInsufficientBuffer() {
        // Test engineDigest with buffer too small
        HMACT64 hmac = new HMACT64(TEST_KEY);
        hmac.engineUpdate(TEST_DATA, 0, TEST_DATA.length);

        byte[] buffer = new byte[10];
        // Should throw exception when buffer is too small
        assertThrows(IllegalStateException.class, () -> hmac.engineDigest(buffer, 0, 10));
    }

    @Test

   1. Definitions.

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   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,
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      "Legal Entity" shall mean the union of the acting entity and all

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,
      and distribution as defined by Sections 1 through 9 of this document.

      "Licensor" shall mean the copyright owner or entity authorized by
      the copyright owner that is granting the License.

      "Legal Entity" shall mean the union of the acting entity and all

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,
      and distribution as defined by Sections 1 through 9 of this document.

      "Licensor" shall mean the copyright owner or entity authorized by
      the copyright owner that is granting the License.

      "Legal Entity" shall mean the union of the acting entity and all

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,
      and distribution as defined by Sections 1 through 9 of this document.

      "Licensor" shall mean the copyright owner or entity authorized by
      the copyright owner that is granting the License.

      "Legal Entity" shall mean the union of the acting entity and all

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,
      and distribution as defined by Sections 1 through 9 of this document.

      "Licensor" shall mean the copyright owner or entity authorized by
      the copyright owner that is granting the License.

      "Legal Entity" shall mean the union of the acting entity and all

or any Secondary License (as applicable), including Contributors.

"Derivative Works" shall mean any work, whether in Source Code or other
form, that is based on (or derived from) the Program and for which the
editorial revisions, annotations, elaborations, or other modifications
represent, as a whole, an original work of authorship.

"Modified Works" shall mean any work in Source Code or other form that

This functionality in this package is mostly captured in the Arena type.
Arenas allocate large chunks of memory for Go values, so they're likely to
be inefficient for allocating only small amounts of small Go values. They're
best used in bulk, on the order of MiB of memory allocated on each use.

Note that by allowing for this limited form of manual memory allocation

        // I'm fully aware that the file could just be moved using File.rename but
        // there are bugs in various JVM that have problems doing this across
        // different filesystem. So we'll incur the small hit to actually copy
        // here and be safe. jvz.
        // ----------------------------------------------------------------------------

        try {