reactor-core/src/main/java/reactor/core/publisher/Flux.java
public final Flux<T> onBackpressureBuffer(int maxSize, BufferOverflowStrategy bufferOverflowStrategy) {
		Objects.requireNonNull(bufferOverflowStrategy, "bufferOverflowStrategy");
		return onAssembly(new FluxOnBackpressureBufferStrategy<>(this, maxSize,
				null, bufferOverflowStrategy));
	}
public final Flux<T> onBackpressureBuffer(int maxSize, BufferOverflowStrategy bufferOverflowStrategy) {
		Objects.requireNonNull(bufferOverflowStrategy, "bufferOverflowStrategy");
		return onAssembly(new FluxOnBackpressureBufferStrategy<>(this, maxSize,
				null, bufferOverflowStrategy));
	}
Request an unbounded demand and push to the returned {@link Flux}, or park the observed
elements if not enough demand is requested downstream, within a {@code maxSize}
limit. Over that limit, the overflow strategy is applied (see {@link BufferOverflowStrategy}).
<p>
Note that for the {@link BufferOverflowStrategy#ERROR ERROR} strategy, the overflow
error will be delayed after the current backlog is consumed.

<p>
<img class="marble" src="doc-files/marbles/onBackpressureBufferWithMaxSizeStrategyDropOldest.svg" alt="">

@reactor.discard This operator discards the buffered overflow elements upon cancellation or error triggered by a data signal,
as well as elements that are rejected by the buffer due to {@code maxSize} (even though
they are passed to the {@code bufferOverflowStrategy} first).


@param maxSize maximum buffer backlog size before overflow strategy is applied
@param bufferOverflowStrategy strategy to apply to overflowing elements

@return a backpressured {@link Flux} that buffers up to a capacity then applies an
overflow strategy