$data = [
'Name' => 'Some name',
];
/* returns the id of the created object */
$salesforceFunctions->create('Account', $data);
$new_data = [
'Name' => 'another name',
];
/* returns statuscode */
$salesforceFunctions->update('Account', $id, $new_data);
$new_data = [
'Name' => 'another name',
];
/* returns statuscode */
$salesforceFunctions->upsert('Account', 'API Name/ Field Name', 'value', $new_data);
$salesforceFunctions->describe('Account');
$salesforceFunctions->customEndpoint('apex/myCustomEndpoint', $data, 200);