httpx crash

bitmask.nim(49)          bitmask
application.nim(534)     run
server.nim(31)           serve
httpx.nim(549)           run
httpx.nim(438)           eventLoop
httpx.nim(355)           processEvents
application.nim(535)     :anonymous
application.nim(503)     handleRequest
asyncmacro.nim(262)      handleContext
asyncmacro.nim(32)       handleContextNimAsyncContinue
application.nim(489)     handleContextIter
context.nim(276)         respond
request.nim(147)         respond
httpx.nim(172)           respond
httpx.nim(146)           send
assertions.nim(30)       failedAssertImpl
assertions.nim(23)       raiseAssert
fatal.nim(49)            sysFatal
[[reraised from:
bitmask.nim(49)          bitmask
application.nim(534)     run
server.nim(31)           serve
httpx.nim(549)           run
httpx.nim(445)           eventLoop
asyncdispatch.nim(1627)  poll
asyncdispatch.nim(1368)  runOnce
asyncdispatch.nim(208)   processPendingCallbacks
asyncfutures.nim(281)    :anonymous
httpx.nim(359)           :anonymous
httpx.nim(217)           onRequestFutureComplete
]]
Error: unhandled exception: httpx.nim(146, 10) `reqGetData.headersFinished` Selector not ready to send. [AssertionDefect]