@Override
    public Iterator<Vertex> readVertices(final InputStream inputStream,
                                         final Function<Attachable<Vertex>, Vertex> vertexAttachMethod,
                                         final Function<Attachable<Edge>, Edge> edgeAttachMethod,
                                         final Direction attachEdgesOfThisDirection) throws IOException {
        return readVertexStrings(inputStream).<Vertex>map(FunctionUtils.wrapFunction(line -> readVertex(new ByteArrayInputStream(line.getBytes()), vertexAttachMethod, edgeAttachMethod, attachEdgesOfThisDirection))).iterator();
    }
Read {@link Vertex} objects from output generated by any of the {@link GraphSONWriter} {@code writeVertex} or
{@code writeVertices} methods or by {@link GraphSONWriter#writeGraph(OutputStream, Graph)}.

@param inputStream a stream containing at least one {@link Vertex} as defined by the accompanying
                   {@link GraphWriter#writeVertices(OutputStream, Iterator, Direction)} or
                   {@link GraphWriter#writeVertices(OutputStream, Iterator)} methods.
@param vertexAttachMethod a function that creates re-attaches a {@link Vertex} to a {@link Host} object.
@param edgeAttachMethod a function that creates re-attaches a {@link Edge} to a {@link Host} object.
@param attachEdgesOfThisDirection only edges of this direction are passed to the {@code edgeMaker}.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/graphson/GraphSONReader.java