The existing implementation of 'LocalRequest::clone()' mistakenly copied
the internal 'Request' pointer from the existing 'LocalRequest' to the
cloned 'LocalRequest'. This resulted in an aliased '*mut Request'
pointer, a clear soundness issue. The fix in this commit is to clone the
internal 'Request', replacing the internal pointer with the newly cloned
'Request' when producing the cloned 'LocalRequest'. A fix that removes
all 'unsafe' code should be explored.
Fixes#1312.
Sergio Benitez