These aren't needed anymore.

Release note: None

This no longer needs to be thread-safe.

Release note: None

This state is already in ReplicaDescriptor.

Release note: None

This was not needed anymore. This should provide a small
but real perf win because we can avoid the context.WithCancel
call for every RPC.

Release note: None

The `OrigTimestamp` was being used to give a timestamp to the
txn in the logical op log because that is the timestamp the
intent is written at. However, the intent can't actually
commit until its `Timestamp`. This was causing issues with
closed timestamps, which forwards the `Txn.Timestamp` but don't
affect the `OrigTimestamp`. Without this change we were hitting
an assertion in the rangefeed package where a new intent looked
like it was below the resolved timestamp.

Release note: None

This change adds a new `EventChanTimeout` configuration to
`rangefeed.Processor`. The config specifies the maximum duration
that `ConsumeLogicalOps` and `ForwardClosedTS` will block on the
Processor's input channel. Once the duration is exceeded, these
methods will stops the processor with an error and tear it down.
This prevents slow consumers from making callers of the two methods
block.

The first method is used downstream of Raft, where blocking due to
slow rangefeed consumers for an unbounded amount of time is unacceptable.
It may require that we resize the processor's input buffer.

A TODO is left about reducing the impact of a single slow consumer
on an entire rangefeed.Processor. This can be left as a future
improvement.

Release note: None

The previous contract for `rangefeed.Stream.Send` was that its
events were unsafe for use after it returned, mandating a clone
if they were stored somewhere. This added extra complication and
will force local RangeFeed rpcs to perform clones even when they're
not necessary. Remove this "optimization" and strengthen the contract.

Release note: None

This commit adds a RangeFeed method to DistSender and teaches it how
to split rangefeeds across ranges and how to manage their individual
lifecycle events.

Release note: None

This commit adjusts the changefeed poller to use RangeFeed
requests when the corresponding cluster setting is enabled.

Release note: None

This PR includes two small perf tweak that came up
which running cdc/w=100/nodes=3/init=true.

Release note: None

Release note: None

These seemed to get stuck without this.

Release note: None

Ranges with expiration-based leases will not function properly
with closed timestamps, which means that we can't establish a
resolved timestamp on ranges that use them. Because of this,
we disallow rangefeeds on these ranges entirely.

This restriction may be lifted in the future.

Release note: None

This change hooks up closed timestamps into rangefeed. It does
so by creating a new closed timestamp subscription and notifying
all ranges with active rangefeed when new closed timestamp entries
arrive. This triggers each rangefeed to check for the maximum closed
timestamp on its range and use this to attempt to move its resolved
timestamp forward.

Eventually this will need some testing tied in with the closedts
package. That will have to wait until the closedts package is set
up to be more easily used in tests from the storage package (right
now `NoopContainer`s are used in tests everywhere). For now, we can
wait for integration testing with cdc.

Release note: None