Performing any long running task or CPU intensive work on transport_worker threads is problematic. This is typically very bad for cluster stability.

This issue has been filed to examine the usage of transport_worked threads by ESQL, with the intention of "offloading" as much as possible, including deserialising large(ish) amounts of data.
x-pack/plugin/esql/compute/src/test/java/org/elasticsearch/compute/operator/exchange/ExchangeServiceTests.java
private final TransportChannel in;
        FilterTransportChannel(TransportChannel in) {
            this.in = in;
        }
        @Override
        public String getProfileName() {
            return in.getProfileName();
        }
        @Override
        public String getChannelType() {
            return in.getChannelType();
        }
        @Override
        public void sendResponse(TransportResponse response) throws IOException {
            in.sendResponse(response);
        }
        @Override
        public void sendResponse(Exception exception) throws IOException {
            in.sendResponse(exception);
        }
    }
}