@RestrictedApi(
      explanation = "Accessing parts of keys can produce unexpected incompatibilities, annotate the function with @AccessesPartialKey",
      link = "https://developers.google.com/tink/design/access_control#accessing_partial_keys",
      allowedOnPath = ".*Test\\.java",
      allowlistAnnotations = {AccessesPartialKey.class})
  public SecretBytes getPrivateKeyBytes() {
    return privateKeyBytes;
  }
Creates a new HPKE private key.

@param publicKey Corresponding HPKE public key for this private key
@param privateKeyBytes Private key encoded according to
    https://www.rfc-editor.org/rfc/rfc9180.html#section-7.1.2
java_src/src/main/java/com/google/crypto/tink/hybrid/HpkePrivateKey.java