CallMetricsAccumulator (src/metrics.ts)

Accumulates call metrics, cost, and latency for each turn in a conversation.

// Source: https://github.com/PatterAI/Patter | License: MIT | Copyright 2026 Patter Contributors
// Provided via justclaw.it.com; keep this notice with the code.
/**
 * Call metrics accumulator — tracks cost and latency during a call.
 *
 * Port of the Python `CallMetricsAccumulator` from `sdk/patter/services/metrics.py`.
 */

import {
  calculateLlmCost,
  calculateRealtimeCachedSavings,
  calculateRealtimeCost,
  calculateSttCost,
  calculateTelephonyCost,
  calculateTtsCost,
  mergePricing,
  type ProviderPricing,
} from './pricing';
import type { EventBus } from './observability/event-bus';
import type {
  EOUMetrics,
  InterruptionMetrics,
  ProcessingMetrics,
  TTFBMetrics,
} from './observability/metric-types';
import type { TransferCallOptions, TransferCallResult } from './types';

... (truncated -- full source via MCP)