/**
 * Sets a custom user location attribute.
 *
 * @param key - The identifier of the custom location attribute. Limited to 255 characters in length, cannot begin with
 *   a $, and can only contain alphanumeric characters and punctuation.
 * @param latitude - The latitude of the user's location (valid values are between -90 to 90 degrees). Passing a null
 *   value for both latitude and longitude will remove this custom attribute from the user.
 * @param longitude - The longitude of the user's location (valid values are between -180 to 180 degrees). Passing a null
 *   value for both latitude and longitude will remove this custom attribute from the user.
 *
 * @returns Resolves to a boolean that indicates whether the update was successfully enqueued. Resolves to undefined
 *   if the SDK is not initialized.
 */
export declare function setCustomUserLocationAttribute(key: string, latitude: number | null, longitude: number | null): Promise<boolean | undefined>;