This commit updates the request FSM to resolve deep futures to
ensure that retried synchronous requests are waited on correctly
and produce side-effects when expected. Previously the results of a
retried request were not being properly brought up to the outermost
layer when a client was attempting to dereference a future because the
request was not a future request.
Adding a way to get the number of retries to events
When a networking error occurs, the future response that is created
for the transaction does not receive an exception until after the
future is waited on. When calling getResponse() in an event that
is emitted after a networking error, the response returned will
be a future with no actual data to use and throws when accessed.
This commit updated these events to return null if the response
of the transaction is a future. In these cases, it means that the
response did not complete successfully. I've also added a new method
to make this more explicit: hasResponse().
Closes#867.
