azure-storage-common/src/Common/Internal/RestProxy.php
protected function addOptionalQueryParam(array &$queryParameters, $key, $value)
    {
        Validate::isArray($queryParameters, 'queryParameters');
        Validate::canCastAsString($key, 'key');
        Validate::canCastAsString($value, 'value');

        if (!is_null($value) && Resources::EMPTY_STRING !== $value) {
            $queryParameters[$key] = $value;
        }
    }
protected function addOptionalQueryParam(array &$queryParameters, $key, $value)
    {
        Validate::isArray($queryParameters, 'queryParameters');
        Validate::canCastAsString($key, 'key');
        Validate::canCastAsString($value, 'value');

        if (!is_null($value) && Resources::EMPTY_STRING !== $value) {
            $queryParameters[$key] = $value;
        }
    }
Adds optional query parameter.

Doesn't add the value if it satisfies empty().

@param array  &$queryParameters The query parameters.
@param string $key              The query variable name.
@param string $value            The query variable value.

@return void