@SuppressWarnings("PMD.UseObjectForClearerAPI")
    public static JdbiExtension externalPostgres(@Nonnull String hostname,
        @Nullable Integer port,
        @Nonnull String database,
        @Nullable String username,
        @Nullable String password) {
        return JdbiExternalPostgresExtension.instance(hostname, port, database, username, password);
    }
Creates an extension that uses an external (outside the scope of an unit test class) postgres database. Using this method requires the postgres JDBC
driver on the classpath.

@param hostname Hostname of the database.
@param port     Port of the database. Can be null, in that case the default port is used.
@param database Database name.
@param username Username to access the database. Can be null.
@param password Password to access the database. Can be null.
@return A {@link JdbiExtension} connected to an external postgres data source.
@see JdbiExternalPostgresExtension
testing/src/main/java/org/jdbi/v3/testing/junit5/JdbiExtension.java