fix: error retrieving keep alive settings

[karenc-bq]

Summary

Calling keepAliveProps.get(...) will throw errors instead of returning undefined because keepAliveProps is not a map object.

Description

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[sophia-bq]

Is keepAliveProps a consistent type? Could add that instead of having any?

[karenc-bq]

I decided to keep it as any so users can pass the keepAliveProps as either a map or an object:

  const keepAliveProps = new Map<string, any>([
      ["keepAlive", true],
      ["keepAliveInitialDelayMillis", 1234]
    ]);

  const keepAliveObj = {
    keepAlive: true,
    keepAliveInitialDelayMillis: 1234
  };