Creates an identical clone of this
Tube.
This method creates an identical pipeline that can be used
concurrently with this pipeline. When the caller of a pipeline
is multi-threaded and need concurrent use of the same pipeline,
it can do so by creating copies through this method.
Implementation Note
It is the implementation's responsibility to call
TubeCloner#add(Tube,Tube) to register the copied pipe
with the original. This is required before you start copying
the other
Tube references you have, or else there's a
risk of infinite recursion.
For most
Tube implementations that delegate to another
Tube, this method requires that you also copy the
Tubethat you delegate to.
For limited number of
Tubes that do not maintain any
thread unsafe resource, it is allowed to simply return
thisfrom this method (notice that even if you are stateless, if you
got a delegating
Tube and that one isn't stateless, you
still have to copy yourself.)
Note that this method might be invoked by one thread while another
thread is executing the other process method. See
the
Codec#copy() for more discussion about this.