docs: public static Pair<Schema,ArrowWritableRecordBatch> readFromFile(FileInputStream input) throws IOException {
          BufferAllocator allocator = new RootAllocator(Long.MAX_VALUE);
          Schema retSchema = null;
          ArrowWritableRecordBatch ret = null;
          SeekableReadChannel channel = new SeekableReadChannel(input.getChannel());
          ArrowFileReader reader = new ArrowFileReader(channel, allocator);
          reader.loadNextBatch();
          retSchema = toDatavecSchema(reader.getVectorSchemaRoot().getSchema());
          //load the batch
          VectorUnloader unloader = new VectorUnloader(reader.getVectorSchemaRoot());
          VectorLoader vectorLoader = new VectorLoader(reader.getVectorSchemaRoot());
          ArrowRecordBatch recordBatch = unloader.getRecordBatch();
  
          vectorLoader.load(recordBatch);
          ret = asDataVecBatch(recordBatch,retSchema,reader.getVectorSchemaRoot());
          ret.setUnloader(unloader);
  
          return Pair.of(retSchema,ret);
  
      }