InputStream.readBytesAsync

void readBytesAsync(size_t count,  int  ioPriority,  gio.cancellable.Cancellable cancellable =  null,  gio.types.AsyncReadyCallback callback =  null)

Request an asynchronous read of count bytes from the stream into a new #GBytes. When the operation is finished callback will be called. You can then call gio.input_stream.InputStream.readBytesFinish to get the result of the operation.

During an async request no other sync and async calls are allowed on stream, and will result in gio.types.IOErrorEnum.Pending errors.

A value of count larger than G_MAXSSIZE will cause a gio.types.IOErrorEnum.InvalidArgument error.

On success, the new #GBytes will be passed to the callback. It is not an error if this is smaller than the requested size, as it can happen e.g. near the end of a file, but generally we try to read as many bytes as requested. Zero is returned on end of file (or if count is zero), but never otherwise.

Any outstanding I/O request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is glib.types.PRIORITY_DEFAULT.

Parameters

`count`	the number of bytes that will be read from the stream
`ioPriority`	the I/O priority of the request
`cancellable`	optional #GCancellable object, null to ignore.
`callback`	a #GAsyncReadyCallback to call when the request is satisfied