presto-main/src/main/java/io/prestosql/dispatcher/QueuedStatementResource.java/QueuedStatementResource/cancelQuery
class QueuedStatementResource:    @DELETE
    @Path("/v1/statement/queued/{queryId}/{slug}/{token}")
    @Produces(APPLICATION_JSON)
    public Response cancelQuery(
            @PathParam("queryId") QueryId queryId,
            @PathParam("slug") String slug,
            @PathParam("token") long token)
    {
        getQuery(queryId, slug, token)
                .cancel();
        return Response.noContent().build();
    }