### Description

The `sendRequest` method is asynchronous and notifies a 
`TransportResponseHandler` when it completes the excecution
(successfully or unsuccessfully). 

When opening the connection we only catch `NodeNotConnectedException`
( https://github.com/elastic/elasticsearch/blob/main/server/src/main/java/org/elasticsearch/transport/TransportService.java#L719 ) which is currently fine as no implementations
throw other type of exception however, it'd be best to catch `Exception` here
so the `handler` gets notified of potential exceptions (as opposed to the caller
having to `try/catch` the call to `sendRequest`)
server/src/main/java/org/elasticsearch/cluster/coordination/CoordinationDiagnosticsService.java
"No master node observed in the last %s, and some master eligible nodes are unable to discover other master "
                        + "eligible nodes",
                    nodeHasMasterLookupTimeframe
                ),
                getDetails(explain, localMasterHistory, null, nodeIdToClusterFormationDescription)
            );
        } else {
            if (anyNodeInClusterReportsQuorumProblems(nodeClusterFormationStateMap)) {
                result = new CoordinationDiagnosticsResult(
                    CoordinationDiagnosticsStatus.RED,
                    String.format(
                        Locale.ROOT,
                        "No master node observed in the last %s, and the master eligible nodes are unable to form a quorum",
                        nodeHasMasterLookupTimeframe
                    ),
                    getDetails(explain, localMasterHistory, null, nodeIdToClusterFormationDescription)
                );
            } else {
                result = new CoordinationDiagnosticsResult(
                    CoordinationDiagnosticsStatus.RED,
                    String.format(
                        Locale.ROOT,
                        "No master node observed in the last %s, and the cause has not been determined.",
                        nodeHasMasterLookupTimeframe
                    ),
                    getDetails(explain, localMasterHistory, null, nodeIdToClusterFormationDescription)
                );
            }
        }
        return result;