public final Flux<T> expand(Function<? super T, ? extends Publisher<? extends T>> expander,
			int capacityHint) {
		return Flux.onAssembly(new MonoExpand<>(this, expander, true, capacityHint));
	}
public final Flux<T> expand(Function<? super T, ? extends Publisher<? extends T>> expander,
			int capacityHint) {
		return Flux.onAssembly(new MonoExpand<>(this, expander, true, capacityHint));
	}
public final Flux < T > expand ( Function < ? super T , ? extends Publisher < ? extends T > > expander , int capacityHint ) { return Flux . onAssembly ( new MonoExpand <> ( this , expander , true , capacityHint ) ) ; }
Recursively expand elements into a graph and emit all the resulting element using
a breadth-first traversal strategy.
<p>
That is: emit the value from this {@link Mono} first, then it each at a first level of
recursion and emit all of the resulting values, then expand all of these at a
second level and so on...
<p>
For example, given the hierarchical structure
<pre>
A
- AA
- aa1
- AB
- ab1
- a1
</pre>

Expands {@code Mono.just(A)} into
<pre>
A
AA
AB
a1
aa1
ab1
</pre>

@param expander the {@link Function} applied at each level of recursion to expand
values into a {@link Publisher}, producing a graph.
@param capacityHint a capacity hint to prepare the inner queues to accommodate n
elements per level of recursion.

@return this Mono expanded breadth-first to a {@link Flux}
Recursively expand elements into a graph and emit all the resulting element using a breadth - first traversal strategy . <p > That is : emit the value from this { @link Mono } first then it each at a first level of recursion and emit all of the resulting values then expand all of these at a second level and so on ... <p > For example given the hierarchical structure <pre > A - AA - aa1 - AB - ab1 - a1 < / pre >