Problems with using a bundler (esbuild, webpack, etc)

We haven't been able to get pulsar-client to work with a bundler like webpack or esbuild. The `pulsar.node` file is not picked up by the bundler and additional files in the library (.html, .cs) end up breaking the build. Even if the bundler is configured to ignore these html/cs files, it fails to export `pulsar.node` file from node_modules into the build directory.

An alternative path is to get webpack/esbuild to ignore `pulsar-client` completely and to manually copy over `pulsar.node` from node_modules. This ends up causing problems because [pulsar-binding.js](https://github.com/apache/pulsar-client-node/blob/master/src/pulsar-binding.js) explicitly looks for the package.json file and for mapbox/node-pre-gyp:

```
const binary = require('@mapbox/node-pre-gyp');

const bindingPath = binary.find(path.resolve(path.join(__dirname, '../package.json')));
```

So it seems like pulsar-client would need to be architected differently to work with webpack/esbuild.

We did finally find a workaround to the problem. Sharing it here for other people who run into this too: we use esbuild to build and package up our node.js app but we add an additional step that creates a simple package.json file with pulsar-client in the parent directory and then run `npm install`. This way we can continue using esbuild to package up our node app but externally inject pulsar-client as a dependency.

Here's an example build.js for esbuild:

```
const esbuild = require("esbuild");
const { copy } = require("esbuild-plugin-copy");
const fs = require("fs-extra");
const path = require("path");
const { execSync } = require("child_process");

// Ensure that native modules, like node-canvas, are bundled correctly
// This however does not work for pulsar-client, see the then() block below
const nativeNodeModulesPlugin = {
name: "native-node-modules",
setup(build) {
build.onResolve({ filter: /\.node$/, namespace: "file" }, (args) => ({
path: require.resolve(args.path, { paths: [args.resolveDir] }),
namespace: "node-file",
}));

build.onLoad({ filter: /.*/, namespace: "node-file" }, (args) => ({
contents: `
import path from ${JSON.stringify(args.path)}
try { module.exports = require(path) }
catch {}
`,
}));

build.onResolve({ filter: /\.node$/, namespace: "node-file" }, (args) => ({
path: args.path,
namespace: "file",
}));

const opts = build.initialOptions;
opts.loader = opts.loader || {};
opts.loader[".node"] = "file";
},
};

esbuild
.build({
entryPoints: ["src/index.ts"],
plugins: [nativeNodeModulesPlugin],
bundle: true,
platform: "node",
target: "node18",
outdir: "build/src",
tsconfig: "tsconfig.json",
sourcemap: true,
// Ignore pulsar-client and related dependencies. These will be installed in the build directory later.
external: ["*.html", "mock-aws-s3", "aws-sdk", "nock", "pulsar-client"],
})
.then(() => {
// pulsar-client does not work when bundled so we install it in the build
// directory as a dependency.

// Get the version of pulsar-client that we are using
const pulsarVersion = require("pulsar-client/package.json").version;
// Create a package.json file in the build directory with pulsar-client as a dependency
const packageJson = {
name: "external-deps",
version: "1.0.0",
dependencies: {
"pulsar-client": `^${pulsarVersion}`,
},
};
// Write the package.json file to the build directory and install the dependencies
fs.writeFileSync(path.join("build", "package.json"), JSON.stringify(packageJson, null, 2));
execSync("cd build && npm install --no-package-lock");
})
.catch(() => process.exit(1));

```

We then launch our app: `cd build && node ./src/index.js`

まず webpack または esbuild で bundling の失敗を再現し、src/pulsar-binding.js と、@mapbox/node-pre-gyp による ../package.json の検索に注目します。node_modules からの pulsar.node と追加の HTML/CS ファイルがどのように扱われるかを追跡します。外部インストールの workaround なしで pulsar-client をパッケージ化して読み込める、文書化またはテスト済みの bundler パスがあれば完了です。

索引モデルが issue の本文から書いたものです。