text: #! /usr/bin/env node
  
  // Licensed to the Apache Software Foundation (ASF) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The ASF licenses this file
  // to you under the Apache License, Version 2.0 (the
  // "License"); you may not use this file except in compliance
  // with the License.  You may obtain a copy of the License at
  //
  //   http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing,
  // software distributed under the License is distributed on an
  // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, either express or implied.  See the License for the
  // specific language governing permissions and limitations
  // under the License.
  
  // @ts-check
  
  const fs = require('fs');
  const path = require('path');
  const extension = process.env.ARROW_JS_DEBUG === 'src' ? '.ts' : '.cjs';
  const { RecordBatch, AsyncMessageReader } = require(`../index${extension}`);
  const { VectorLoader } = require(`../targets/apache-arrow/visitor/vectorloader`);
  
  (async () => {
  
      const readable = process.argv.length < 3 ? process.stdin : fs.createReadStream(path.resolve(process.argv[2]));
      const reader = new AsyncMessageReader(readable);
  
      let schema, recordBatchIndex = 0, dictionaryBatchIndex = 0;
  
      for await (const message of reader) {
  
          let bufferRegions = [];
  
          if (message.isSchema()) {
              schema = message.header();
              continue;
          } else if (message.isRecordBatch()) {
              const header = message.header();
              bufferRegions = header.buffers;
              const body = await reader.readMessageBody(message.bodyLength);
              const recordBatch = loadRecordBatch(schema, header, body);
              console.log(`record batch ${++recordBatchIndex}: ${JSON.stringify({
                  offset: body.byteOffset,
                  length: body.byteLength,
                  numRows: recordBatch.length,
              })}`);
          } else if (message.isDictionaryBatch()) {
              const header = message.header();
              bufferRegions = header.data.buffers;
              const type = schema.dictionaries.get(header.id);
              const body = await reader.readMessageBody(message.bodyLength);
              const recordBatch = loadDictionaryBatch(header.data, body, type);
              console.log(`dictionary batch ${++dictionaryBatchIndex}: ${JSON.stringify({
                  offset: body.byteOffset,
                  length: body.byteLength,
                  numRows: recordBatch.length,
                  dictionaryId: header.id,
              })}`);
          }
  
          bufferRegions.forEach(({ offset, length }, i) => {
              console.log(`\tbuffer ${i + 1}: { offset: ${offset},  length: ${length} }`);
          });
      }
  
      await reader.return();
  
  })().catch((e) => { console.error(e); process.exit(1); });
  
  function loadRecordBatch(schema, header, body) {
      return new RecordBatch(schema, header.length, new VectorLoader(body, header.nodes, header.buffers, new Map()).visitMany(schema.fields));
  }
  
  function loadDictionaryBatch(header, body, dictionaryType) {
      return RecordBatch.new(new VectorLoader(body, header.nodes, header.buffers, new Map()).visitMany([dictionaryType]));
  }
  