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Closes#36359
PiperOrigin-RevId: 625183028
1. All greeter servers now support flag `--port` to customize the listen
port.
2. All client implementation now have `--target` flag to specify the
server location.
3. ABSL is used to parse the flags to reduce the amount of boilerplate
code in the examples.
Fixes: #26989
* De-experimentalize callback API
* Make FromServerContext based on ServerContextBase
* Fix lambda
* Fix headers
* De-experimentalize tests
* clang-format
* Fix consistency checks
* wip
* Fix const-ness of callback client read RPC requests
* Fix golden file
* Give full route_guide callback client example with Hold etc
* Complete example route-guide server
* De-experimentalize test services
* Omit unneeded using
* Remove some uses of non-experimental macro from test
* clang-format examples
* De-experimentalize async stub calls
* Remove experimental namespace use in qps, ubms
* De-experimentalize alarms, generic stubs, and context allocator
* De-experimentalize SetContextAllocator
* clang-format
* Fix conflicts
* Leave obsolete API in place until users can be migrated
The example should be build with grpc++, not grpc++_unsecure.
For some reason in some branches like master, both versions are built in
so problem not detected. This problem surfaced in 1.28x so needs to be
fixed to link with the correct grpc++.
The Google Benchmark CMake build needs CMake 3.5.1 or newer. CMake 3.5.1
was released May 24, 2016 and is available in Debian stable and Ubuntu
16.04 and 18.04.