+export type PoolType = keyof typeof PoolTypes
+
+/**
+ * Enumeration of pool events.
+ */
+export const PoolEvents: Readonly<{
+ ready: 'ready'
+ busy: 'busy'
+ full: 'full'
+ empty: 'empty'
+ destroy: 'destroy'
+ error: 'error'
+ taskError: 'taskError'
+ backPressure: 'backPressure'
+}> = Object.freeze({
+ ready: 'ready',
+ busy: 'busy',
+ full: 'full',
+ empty: 'empty',
+ destroy: 'destroy',
+ error: 'error',
+ taskError: 'taskError',
+ backPressure: 'backPressure'
+} as const)
+
+/**
+ * Pool event.
+ */
+export type PoolEvent = keyof typeof PoolEvents
+
+/**
+ * Pool information.
+ */
+export interface PoolInfo {
+ readonly version: string
+ readonly type: PoolType
+ readonly worker: WorkerType
+ readonly started: boolean
+ readonly ready: boolean
+ readonly defaultStrategy: WorkerChoiceStrategy
+ readonly strategyRetries: number
+ readonly minSize: number
+ readonly maxSize: number
+ /** Pool utilization. */
+ readonly utilization?: number
+ /** Pool total worker nodes. */
+ readonly workerNodes: number
+ /** Pool stealing worker nodes. */
+ readonly stealingWorkerNodes?: number
+ /** Pool idle worker nodes. */
+ readonly idleWorkerNodes: number
+ /** Pool busy worker nodes. */
+ readonly busyWorkerNodes: number
+ readonly executedTasks: number
+ readonly executingTasks: number
+ readonly queuedTasks?: number
+ readonly maxQueuedTasks?: number
+ readonly backPressure?: boolean
+ readonly stolenTasks?: number
+ readonly failedTasks: number
+ readonly runTime?: {
+ readonly minimum: number
+ readonly maximum: number
+ readonly average?: number
+ readonly median?: number
+ }
+ readonly waitTime?: {
+ readonly minimum: number
+ readonly maximum: number
+ readonly average?: number
+ readonly median?: number
+ }
+}
+
+/**
+ * Worker node tasks queue options.
+ */
+export interface TasksQueueOptions {
+ /**
+ * Maximum tasks queue size per worker node flagging it as back pressured.
+ *
+ * @defaultValue (pool maximum size)^2
+ */
+ readonly size?: number
+ /**
+ * Maximum number of tasks that can be executed concurrently on a worker node.
+ *
+ * @defaultValue 1
+ */
+ readonly concurrency?: number
+ /**
+ * Whether to enable task stealing on idle.
+ *
+ * @defaultValue true
+ */
+ readonly taskStealing?: boolean
+ /**
+ * Whether to enable tasks stealing under back pressure.
+ *
+ * @defaultValue false
+ */
+ readonly tasksStealingOnBackPressure?: boolean
+ /**
+ * Queued tasks finished timeout in milliseconds at worker node termination.
+ *
+ * @defaultValue 2000
+ */
+ readonly tasksFinishedTimeout?: number
+}