Description
current implemention in version 5.1, when connection gracefully shutdown and receives a single HEADERS frame with END_HEADERS flag set, it will throws "Stream refused" exception, not sure about this.
As RFC7540 section 4.3 defines, looks like single HEADERS frame should be consumed.
This code in org/apache/hc/core5/http2/impl/nio/AbstractH2StreamMultiplexer.java:1073