/**
 * Decorator that conditionally executes a method based on a supplied condition function.
 * Unlike the @Condition decorator which waits for a condition to be met, @Conditional
 * immediately skips the method execution if the condition is not met.
 *
 * ## Parameters
 * @param {() => boolean} conditionFn - Function that determines if the method should execute.
 *   Should return true to allow execution, false to skip.
 *
 * ## Features
 * - **Conditional Execution**: Skips method execution if condition is not met
 * - **Synchronous Evaluation**: Condition is checked immediately before method execution
 * - **No Waiting**: Unlike @Condition, does not wait for condition to become true
 * - **State-Aware**: Can access workflow state through the condition function
 *
 * ## Common Use Cases
 * 1. Skip processing based on workflow state
 * 2. Implement feature flags in workflows
 * 3. Control execution flow based on configuration
 * 4. Implement optional workflow steps
 *
 * ## Usage Examples
 * ```typescript
 * class WorkflowExample {
 *   private isEnabled = false;
 *
 *   // Method will only execute if isEnabled is true
 *   @Conditional(() => this.isEnabled)
 *   protected async processData(): Promise<void> {
 *     // This code is skipped if isEnabled is false
 *   }
 *
 *   // Complex condition combining multiple states
 *   @Conditional(() => this.isEnabled && this.hasData && !this.isProcessing)
 *   protected async complexOperation(): Promise<void> {
 *     // Only executes if all conditions are met
 *   }
 * }
 * ```
 *
 * ## Notes
 * - Condition function should be pure and deterministic
 * - Avoid side effects in the condition function
 * - Can be combined with other decorators like @Action or @Mutex
 * - Different from @Condition which waits for conditions to be met
 *
 * @see Condition
 * @see Action
 * @see Mutex
 */
export declare function Conditional<T = any>(condition: (this: T, ...args: any[]) => boolean | Promise<boolean>): MethodDecorator;