Method once

src/dap/api.d.ts:1258–1258

(
      request: 'initialized',
      filter?: (event: InitializedEventParams) => boolean,
    )

    on(request: 'initialized', handler: (params: InitializedEventParams) => void): void;
    off(request: 'initialized', handler: (params: InitializedEventParams) => void): void;
    once(
      request: 'initialized',
      filter?: (event: InitializedEventParams) => boolean,
    ): Promise<InitializedEventParams>;