code: public ApnsClientBuilder setClientCredentials(final X509Certificate clientCertificate, final PrivateKey privateKey, final String privateKeyPassword) {
          this.clientCertificate = clientCertificate;
          this.privateKey = privateKey;
          this.privateKeyPassword = privateKeyPassword;
  
          return this;
      }
docs: <p>Sets the TLS credentials for the client under construction. Clients constructed with TLS credentials will use
  TLS-based authentication when sending push notifications.</p>
  
  <p>Clients may not have both TLS credentials and a signing key.</p>
  
  @param clientCertificate the certificate to be used to identify the client to the APNs server
  @param privateKey the private key for the client certificate
  @param privateKeyPassword the password to be used to decrypt the private key; may be {@code null} if the private
  key does not require a password
  
  @return a reference to this builder
  
  @since 0.8