public static final KeyTemplate aes256GcmHkdf1MBTemplate() {
    return exceptionIsBug(
        () ->
            KeyTemplate.createFrom(
                AesGcmHkdfStreamingParameters.builder()
                    .setKeySizeBytes(32)
                    .setDerivedAesGcmKeySizeBytes(32)
                    .setCiphertextSegmentSizeBytes(1024 * 1024)
                    .setHkdfHashType(AesGcmHkdfStreamingParameters.HashType.SHA256)
                    .build()));
  }
@return a {@link KeyTemplate} that generates new instances of AesGcmHkdfStreaming keys with the
    following parameters:
    <ul>
      <li>Size of the main key: 32 bytes
      <li>HKDF algo: HMAC-SHA256
      <li>Size of AES-GCM derived keys: 32 bytes
      <li>Ciphertext segment size: 1MB
    </ul>
java_src/src/main/java/com/google/crypto/tink/streamingaead/AesGcmHkdfStreamingKeyManager.java