private @NonNull CompletableFuture<ArgumentParseResult<Object>> fail(final @NonNull Throwable exception) {
            return ArgumentParseResult.failureFuture(exception);
        }
Helper class to parse the command input queue into flags
and flag values. On failure the intermediate results
can be obtained, which are used for providing suggestions.
cloud-core/src/main/java/org/incendo/cloud/parser/flag/CommandFlagParser.java