get rawSrc() {
    if (this._rawSrc) {
      return this._rawSrc;
    }

    const err = new Error(`Asset.rawSrc getter: Asset isn't loaded: ${this}`);
    if (this.assetGraph) {
      this.assetGraph.warn(err);
    } else {
      throw err;
    }
  }
Get or set the raw source of the asset.

If the internal state has been changed since the asset was
initialized, it will automatically be reserialized when this
property is retrieved.

@example
const htmlAsset = new AssetGraph().addAsset({
  type: 'Html',
  rawSrc: new Buffer('<html><body>Hello!</body></html>')
});
htmlAsset.parseTree.body.innerHTML = "Bye!";
htmlAsset.markDirty();
htmlAsset.rawSrc.toString(); // "<html><body>Bye!</body></html>"

@type {Buffer}