Expose "module" exports in dev/hmr

[bjufre]

As it stands right now Vite HMR API is quite awesome and covers the majority if not all of the possible needs for us devs.
Nonetheless, sometimes seems to be necessary to have knowledge of how the module exports look like. This is something that one can get via import.meta.hot.accept(module => ...); nonetheless, this will only trigger during a hot update. There are hmr implementations that depend on the module, like the react-hot-loader. Or to implement a more robust @vitejs/plugin-react-refresh where we one can delegate the registration of class components (which right now it doesn't allow), to the runtime with something that would look roughly:
RefreshRuntime.isReactRefreshBoundary(module) where isReactRefreshBoundary:

export function isReactRefreshBoundary(moduleExports) {
  for (let key in moduleExports) {
      let _c = moduleExports[key];
      if (RefreshRuntime.isLikelyComponentType(_c)) {
          $RefreshReg$(_c, _c.displayName || _c.name);
      }
  }
  if (RefreshRuntime.isLikelyComponentType(moduleExports)) {
      return true;
  }
  if (moduleExports == null || typeof moduleExports !== 'object') {
      // Exit if we can't iterate over exports.
      return false;
  }
  let hasExports = false;
  let areAllExportsComponents = true;
  for (const key in moduleExports) {
      hasExports = true;
      if (key === '__esModule') {
          continue;
      }
      const desc = Object.getOwnPropertyDescriptor(moduleExports, key);
      if (desc && desc.get) {
          // Don't invoke getters as they may have side effects.
          return false;
      }
      const exportValue = moduleExports[key];
      if (!RefreshRuntime.isLikelyComponentType(exportValue)) {
          areAllExportsComponents = false;
      }
  }
  return hasExports && areAllExportsComponents;
};

Maybe to follow a little bit, it could be exposed under: import.meta.module or import.meta.hot.module 🤔 ?