### 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/PublicationTransportHandler.java
private long fullStateCount;
        private long totalUncompressedFullStateBytes;
        private long totalCompressedFullStateBytes;
        private long diffCount;
        private long totalUncompressedDiffBytes;
        private long totalCompressedDiffBytes;
        public synchronized void serializedFullState(long uncompressedBytes, int compressedBytes) {
            fullStateCount += 1;
            totalUncompressedFullStateBytes += uncompressedBytes;
            totalCompressedFullStateBytes += compressedBytes;
        }
        public synchronized void serializedDiff(long uncompressedBytes, int compressedBytes) {
            diffCount += 1;
            totalUncompressedDiffBytes += uncompressedBytes;
            totalCompressedDiffBytes += compressedBytes;
        }
        public synchronized ClusterStateSerializationStats getSerializationStats() {
            return new ClusterStateSerializationStats(
                fullStateCount,
                totalUncompressedFullStateBytes,
                totalCompressedFullStateBytes,
                diffCount,
                totalUncompressedDiffBytes,
                totalCompressedDiffBytes
            );
        }
    }
}