private File getTrustStorePkcs12File() throws IOException {
    if (trustStorePkcs12File == null) {
      trustStorePkcs12File = File.createTempFile(TRUST_STORE_PREFIX,
        KeyStoreFileType.PKCS12.getDefaultFileExtension(), tempDir);
      trustStorePkcs12File.deleteOnExit();
      generateTrustStorePkcs12File();
    }
    return trustStorePkcs12File;
  }
Returns the path to the trust store file in the given format (JKS or PEM). Note that the file
is created lazily, the first time this method is called. The trust store file is temporary and
will be deleted on exit.
@param storeFileType the store file type (JKS or PEM).
@return the path to the trust store file.
@throws IOException if there is an error creating the trust store file.
hbase-common/src/test/java/org/apache/hadoop/hbase/io/crypto/tls/X509TestContext.java