* Enable retries by default, but add a separate arg for hedging.
* don't need to explicitly enable retries in xDS config selector
* clang-format
* don't need retry_enabled bit anymore
* fix HTTP client filter to restore the send_message op in the batch
* fix retry cancellation when a batch fails on call attempt
* fix clang-tidy
* fix client channel to pass down batches even after cancellation
* fix retry code to pass transport stats back up to the surface
* add some missing payload propagation
* fix retry handling of callbacks for pending batches
* avoid scheduling the same callback twice
* fix some trace messages
* don't avoid starting recv_initial_metadata or recv_message due to recv_trailing_metadata already being started internally
* avoid restarting recv_trailing_metadata after commit if we've already started it internally
* use fast path when retries are not configured
src/core. exec_ctx is now a thread_local pointer of type ExecCtx instead of
grpc_exec_ctx which is initialized whenever ExecCtx is instantiated. ExecCtx
also keeps track of the previous exec_ctx so that nesting of exec_ctx is
allowed. This means that there is only one exec_ctx being used at any
time. Also, grpc_exec_ctx_finish is called in the destructor of the
object, and the previous exec_ctx is restored to avoid breaking current
functionality. The code still explicitly calls grpc_exec_ctx_finish
because removing all such instances causes the code to break.
Most core end2end tests are written around a single RPC with an explicit
deadline. Currently, this deadline is calculated before bringing up the
test fixture, and thus time spent bringing up the test fixture is taken
from the time allotted to the RPC.
This change moves the calculation of these deadlines immediately before
call creation. Additionally, the functions that calculate these
deadlines have been renamed from 'xx_seconds_time()' to
'xx_seconds_from_now()' for clarity.