@Override
    public String getFlowExecutionKey(final HttpServletRequest request) {
        var executionKey = request.getParameter(DEFAULT_FLOW_EXECUTION_KEY_PARAMETER);
        if (StringUtils.isBlank(executionKey) && HttpMethod.POST.matches(request.getMethod())) {
            val parameters = WebUtils.getHttpRequestParametersFromRequestBody(request);
            executionKey = parameters.get(DEFAULT_FLOW_EXECUTION_KEY_PARAMETER);
        }
        return executionKey;
    }
Default flow execution key parameter name, {@value}.
Same as that used by {@link DefaultFlowUrlHandler}.
core/cas-server-core-webflow-api/src/main/java/org/apereo/cas/web/flow/CasDefaultFlowUrlHandler.java