Prevent multiple calls to API, even if data not retrieved

[MikeiLL]

We are getting many and frequent calls to the MBO api if the desired key isn't present in the API result.

Perhaps we want to create some kind of transient, even an empty array, for a certain period of time, so that we aren't doing repeat calls for data that isn't forthcoming.

Not sure exactly how that would work yet:

		if ( false === get_transient( 'mz_mbo_services' ) ) {

			$this->get_mbo_results();

			if ( ! is_object( $this->mb ) ) {
				return 'Check your MBO connection.';
			}

			try {
				$result = $this->mb->GetServices();
			} catch ( \Exception $e ) {
				return false;
			}

			if ( array_key_exists( 'Services', $result ) ) {
				if ( ! empty( $result['Services'] ) ) {
					set_transient( 'mz_mbo_services', $result, 86400 );
				}
				if ( empty( $result['Services'] ) ) {
					set_transient( 'mz_mbo_services', array(), 86400 );
				}
			}
		} else {

			$result = get_transient( 'mz_mbo_services' );

		}

Wait... isn't that already happening? Look here:

                               if ( empty( $result['Services'] ) ) {
					set_transient( 'mz_mbo_services', array(), 86400 );
				}