message: create function for multiple auth header
diff: import { RecordClient } from "./client/RecordClient";
  import { DefaultHttpClient } from "./http/";
  +import { buildChildren } from "@babel/types";
  -export type Auth = {
  +export type Auth = ApiTokenAuth | PasswordAuth | SessionAuth;
  +
  +type ApiTokenAuth = {
  apiToken: string;
  };
  +type PasswordAuth = {
  + username: string;
  + password: string;
  +};
  +
  +type SessionAuth = {};
  +
  export class KintoneAPIClient {
  record: RecordClient;
  constructor({ subdomain, auth }: { subdomain: string; auth: Auth }) {
  - const headers = { "X-Cybozu-API-Token": auth.apiToken };
  + const headers = this.buildAuthHeaders(auth);
  const url = `https://${subdomain}.cybozu.com/`;
  const httpClient = new DefaultHttpClient({ url, headers });
  this.record = new RecordClient(httpClient);
  }
  +
  + private buildAuthHeaders(auth: Auth) {
  + if ("username" in auth) {
  + const { username, password } = auth;
  + return {
  + "X-Cybozu-Authorization": Buffer.from(
  + `${username}:${password}`
  + ).toString("base64")
  + };
  + }
  + if ("apiToken" in auth) {
  + return { "X-Cybozu-API-Token": auth.apiToken };
  + }
  + return { "X-Requested-With": "XMLHttpRequest" };
  + }
  }
  