How to use the flatbuffers.flatbuffers.ByteBuffer function in flatbuffers

public async getPathInfo(path: string): Promise {
    const builder = new flatbuffers.Builder(256);
    const pathOff = builder.createString(path);

    sz.BrowseRequest.startBrowseRequest(builder);
    sz.BrowseRequest.addPath(builder, pathOff);
    sz.BrowseRequest.addRecursive(builder, toFbLong(1));
    const off = sz.BrowseRequest.endBrowseRequest(builder);
    builder.finish(off);
    const requestPayload = builder.asUint8Array();

    // Send the request
    const r = await this.binaryRouter.post('files/getPathInfo', requestPayload);
    const buf = new flatbuffers.ByteBuffer(r);
    const response = sz.BrowseResponse.getRootAsBrowseResponse(buf);
    const pathInfo = this.convert(response);

    if (this.verboseResponseLog) {
      this.logger.debug(`Browse: ${JSON.stringify(pathInfo, null, 4)}`);
    }

    return pathInfo;
  }

sz.AddConnectionRequest.addCheckForCycles(builder, cycleDetection);
    const off = sz.AddConnectionRequest.endAddConnectionRequest(builder);
    builder.finish(off);

    const requestPayload = builder.asUint8Array();

    const result = await this.binaryRouter.post('graph/addConnection', requestPayload);

    if (!result.length) {
      // Succesfully added connection
      this.logger.info(`Added connection: ['${source.id}' ⟶ '${target.id}'] from graph [id: '${graphId}']`);

      return connection;
    } else {
      // Cycle detected, read the repsonse
      const buf = new flatbuffers.ByteBuffer(result);
      const response = sz.AddNodeResponse.getRootAsAddNodeResponse(buf);
      throw new Error('Cycle detection not yet implemented!');
    }
  }

builder.finish(off);

    const requestPayload = builder.asUint8Array();

    const result = await this.binaryRouter.post('graph/addConnection', requestPayload);

    if (!result.length) {
      // Succesfully added connection
      this.logger.info(
        `Added connection: ['${source.idString}' ⟶ '${target.idString}'] from graph [id: '${graphId.toString()}']`
      );

      return connection;
    } else {
      // Cycle detected, read the repsonse
      const buf = new flatbuffers.ByteBuffer(result);
      const response = sz.AddNodeResponse.getRootAsAddNodeResponse(buf);
      throw 'Cycle detection not yet implemented!';
    }
  }

export function deserialize(bytes: Uint8Array) {
    if (!bytes.subarray(0, 7).every((v, i) => magicbytes[i] === v))
        throw new Error('Not a FlatGeobuf file')

    const bb = new flatbuffers.ByteBuffer(bytes)
    const headerLength = bb.readUint32(magicbytes.length)
    bb.setPosition(magicbytes.length + SIZE_PREFIX_LEN)
    const header = Header.getRoot(bb)
    const count = header.featuresCount().toFloat64()

    const columns: ColumnMeta[] = []
    for (let j = 0; j < header.columnsLength(); j++) {
        const column = header.columns(j)
        columns.push(new ColumnMeta(column.name(), column.type()))
    }
    const headerMeta = new HeaderMeta(header.geometryType(), columns)

    let offset = magicbytes.length + SIZE_PREFIX_LEN + headerLength

    const indexNodeSize = header.indexNodeSize()
    if (indexNodeSize > 0)

encode(encoder: Encoder, init: buffer): Result {
    const byteBuffer = new flatbuffers.ByteBuffer(this.data)
    const chageLog = new ChangeLog()
    ChangeLog.getRootAsChangeLog(byteBuffer, chageLog)
    return ChangeLog.decode(chageLog, encoder, init)
  }

public async getAllGraphTypeDescriptions(): Promise {
    const result = await this.binaryRouter.get('general/getAllGraphTypeDescriptions');
    let buf = new flatbuffers.ByteBuffer(result);
    let response = sz.GetAllGraphTypeDescriptionsResponse.getRootAsGetAllGraphTypeDescriptionsResponse(buf);

    this.logger.info(`Number of graph types: ${response.graphsTypesLength()}`);

    let graphDesc: model.GraphTypeDescription[] = [];

    for (let g = 0; g < response.graphsTypesLength(); ++g) {
      graphDesc.push(conversions.toGraphTypeDescription(response.graphsTypes(g)));
    }

    if (this.verboseResponseLog) {
      this.logger.debug(`GraphDescriptions: ${JSON.stringify(graphDesc)}`);
    }

    return graphDesc;
  }

export async function* deserializeStream(
    stream: ReadableStream) {
    const reader = slice(stream)
    let bytes = await reader.slice(8)
    if (!bytes.every((v, i) => magicbytes[i] === v))
        throw new Error('Not a FlatGeobuf file')
    bytes = await reader.slice(4)
    let bb = new flatbuffers.ByteBuffer(bytes)
    const headerLength = bb.readUint32(0)
    bytes = await reader.slice(headerLength)
    bb = new flatbuffers.ByteBuffer(bytes)
    const header = Header.getRoot(bb)
    const count = header.featuresCount().toFloat64()

    const columns: ColumnMeta[] = []
    for (let j = 0; j < header.columnsLength(); j++) {
        const column = header.columns(j)
        columns.push(new ColumnMeta(column.name(), column.type()))
    }
    const headerMeta = new HeaderMeta(header.geometryType(), columns)

    const indexNodeSize = header.indexNodeSize()
    if (indexNodeSize > 0)
        await reader.slice(tree.size(count, indexNodeSize) + (count * FEATURE_OFFSET_LEN))

public async execute(): Promise {
    const result = await this.binaryRouter.post('graph/execute', this.createBinaryData(null));
    const buf = new flatbuffers.ByteBuffer(result);
  }

columns.push(new ColumnMeta(column.name(), column.type()))
    }
    const headerMeta = new HeaderMeta(header.geometryType(), columns)

    const indexNodeSize = header.indexNodeSize()
    if (indexNodeSize > 0)
        await reader.slice(tree.size(count, indexNodeSize) + (count * FEATURE_OFFSET_LEN))

    for (let i = 0; i < count; i++) {
        bytes = await reader.slice(4)
        bb = new flatbuffers.ByteBuffer(bytes)
        const featureLength = bb.readUint32(0)
        bytes = await reader.slice(featureLength)
        const bytesAligned = new Uint8Array(featureLength + 4)
        bytesAligned.set(bytes, 4)
        bb = new flatbuffers.ByteBuffer(bytesAligned)
        bb.setPosition(SIZE_PREFIX_LEN)
        const feature = Feature.getRoot(bb)
        yield fromFeature(feature, headerMeta, createGeometry, createFeature)
    }
}

export function deserialize(
        bytes: Uint8Array,
        createGeometry: ICreateGeometry,
        createFeature: ICreateFeature): IFeature[] {
    if (!bytes.subarray(0, 7).every((v, i) => magicbytes[i] === v))
        throw new Error('Not a FlatGeobuf file')

    const bb = new flatbuffers.ByteBuffer(bytes)
    const headerLength = bb.readUint32(magicbytes.length)
    bb.setPosition(magicbytes.length + SIZE_PREFIX_LEN)
    const header = Header.getRoot(bb)
    const count = header.featuresCount().toFloat64()

    const columns: ColumnMeta[] = []
    for (let j = 0; j < header.columnsLength(); j++) {
        const column = header.columns(j)
        columns.push(new ColumnMeta(column.name(), column.type()))
    }
    const headerMeta = new HeaderMeta(header.geometryType(), columns)

    let offset = magicbytes.length + SIZE_PREFIX_LEN + headerLength

    const indexNodeSize = header.indexNodeSize()
    if (indexNodeSize > 0)