class sender :src:#async_in_channel -> dst:Unix.file_descr -> ?close_src:bool -> ?close_dst:bool -> Unixqueue.event_system ->[unit]Uq_engines.engine
src input channel to the
dst file descriptor. The engine attaches immediately to the
event system, and detaches automatically.
By default, both the file descriptor and the output channel are closed when the engine stops operation, either successfully or because of an error.
The semantics of the engine is undefined if dst is not a
stream-oriented descriptor.
The engine goes to `Error state when either reading from src
or writing to dst raises an unexpected exception.
For every file descriptor event, the state is advanced from
`Working n to `Working (n+1).
TODO: This class cannot yet cope with Win32 named pipes.
close_src : Whether to close src when the engine stops
(default: true)close_dst : Whether to close dst when the engine stops
(default: true)