[bugfix] Fixes async IO operations stalling even after socket is closed. (#11232)

lib/pure/includes/oserr.nim

@@ -57,8 +57,10 @@ proc osErrorMsg*(errorCode: OSErrorCode): string =
     if errorCode != OSErrorCode(0'i32):
       result = $c_strerror(errorCode.int32)
 
-proc raiseOSError*(errorCode: OSErrorCode; additionalInfo = "") {.noinline.} =
-  ## Raises an `OSError exception <system.html#OSError>`_.
+proc newOSError*(
+  errorCode: OSErrorCode, additionalInfo = ""
+): owned(ref OSError) {.noinline.} =
+  ## Creates a new `OSError exception <system.html#OSError>`_.
   ##
   ## The ``errorCode`` will determine the
   ## message, `osErrorMsg proc <#osErrorMsg,OSErrorCode>`_ will be used
@@ -82,7 +84,14 @@ proc raiseOSError*(errorCode: OSErrorCode; additionalInfo = "") {.noinline.} =
     e.msg.addQuoted additionalInfo
   if e.msg == "":
     e.msg = "unknown OS error"
-  raise e
+  return e
+
+proc raiseOSError*(errorCode: OSErrorCode, additionalInfo = "") {.noinline.} =
+  ## Raises an `OSError exception <system.html#OSError>`_.
+  ##
+  ## Read the description of the `newOSError proc <#newOSError,OSErrorCode,string>`_ to learn
+  ## how the exception object is created.
+  raise newOSError(errorCode, additionalInfo)
 
 {.push stackTrace:off.}
 proc osLastError*(): OSErrorCode {.sideEffect.} =