libspdylay-dev 1.3.2-2.1build2 (s390x binary) in ubuntu focal

 This library provides SPDY version 2, 3 and 3.1 framing layer implementation.
 It does not perform any I/O operations. When the library needs them, it calls
 the callback functions provided by the application. It also does not include
 any event polling mechanism, so the application can freely choose the way of
 handling events
 .
 This package ships the development files.