UpstreamPullRequest

declare const NoUpstream: (activeDownstreamCount: number) => UpstreamPullRequest<never>;

declare const Pulled: <A>(value: A) => UpstreamPullRequest<A>;

declare const match: {
  <A, Z>(options: {
    readonly onNoUpstream: (activeDownstreamCount: number) => Z;
    readonly onPulled: (value: A) => Z;
  }): (self: UpstreamPullRequest<A>) => Z;
  <A, Z>(
    self: UpstreamPullRequest<A>,
    options: {
      readonly onNoUpstream: (activeDownstreamCount: number) => Z;
      readonly onPulled: (value: A) => Z;
    },
  ): Z;
};

interface NoUpstream extends Variance<never> {
  readonly _tag: "NoUpstream";
  readonly activeDownstreamCount: number;
}

interface Pulled<out A> extends Variance<A> {
  readonly _tag: "Pulled";
  readonly value: A;
}

type UpstreamPullRequest<A> = Pulled<A> | NoUpstream;

declare const isNoUpstream: <A>(self: UpstreamPullRequest<A>) => self is NoUpstream;

declare const isPulled: <A>(self: UpstreamPullRequest<A>) => self is Pulled<A>;

declare const isUpstreamPullRequest: (u: unknown) => u is UpstreamPullRequest<unknown>;

declare const UpstreamPullRequestTypeId: unique symbol;

type UpstreamPullRequestTypeId = typeof UpstreamPullRequestTypeId;