readSyncStep2 = (decoder, doc, transactionOrigin) => {
  try {
    Y.applyUpdate(doc, decoding.readVarUint8Array(decoder), transactionOrigin);
  } catch (error) {
    // This catches errors that are thrown by event handlers
    console.error('Caught error while handling a Yjs update', error);
  }
}
Read and apply Structs and then DeleteStore to a y instance.

@param {decoding.Decoder} decoder
@param {Y.Doc} doc
@param {any} transactionOrigin