import type { Context } from "@opentelemetry/api";
import type { ReadableSpan, Span, SpanProcessor } from "@opentelemetry/sdk-trace-base";
/**
 * A SpanProcessor that provides a hook to execute custom logic
 * just before a span is ended.
 *
 * This allows for capturing or modifying span data at the precise moment
 * the span is about to be finished, while it is still writable.
 *
 * Usage:
 * Extend this class and implement the onEnding method with custom logic.
 * Override the onStart method if needed to set up any required state.
 * The onEnding method will be called just before the span's end() method
 * is invoked.
 *
 * Example:
 * ```typescript
 * class CustomSpanProcessor extends OnEndingHookSpanProcessor {
 *  onEnding(span: Span, context: Context): void {
 *     // Custom logic to execute before the span ends
 *     span.setAttribute("custom.attribute", "value");
 *   }
 * }
 * ```
 */
export declare abstract class OnEndingHookSpanProcessor implements SpanProcessor {
    /**
     * Hook method called just before a span is ended.
     * @param span The span that is about to end.
     */
    abstract onEnding(span: Span): void;
    onStart(span: Span, _context: Context): void;
    onEnd(_span: ReadableSpan): void;
    forceFlush(): Promise<void>;
    shutdown(): Promise<void>;
}