implement connection step specific callbacks

implementation of callbacks returning directly the useful parameters,
which shall avoid the modification of api object data by the user. this
state is not stable.
Revert "implement connection step specific callbacks"

This reverts commit 33b5e833e71f3bbf322dbd563b822e5307f67c3b.
Revert 33b5e83..19b5eb1

This rolls back to commit 33b5e833e71f3bbf322dbd563b822e5307f67c3b.
implementation of data specific callback

implementation of different callback types providing a protection
against un-wanted/allowed data manipulation of the api objects.
implementation of a data sharing mechanism between threads
implementation of a thread-specific data access