When executing a sequence like: a>b>c>d>, if we get a failure in the middle of execution like:
a
b
c
fail
Then we re-start from the beginning:
a
b
c
d
this is synchronous
If, however, we have the same sequence to execute: a>b>c>d>, and we have a failure in the middle:
a
b
c
fail
...but instead of restarting from the beginning, we re-start from the point of failure:
c
d
...this is know as asynchronous.
