Forgot to declare the header.

BUILD

@@ -206,6 +206,7 @@ GRPCXX_PUBLIC_HDRS = [
     "include/grpcpp/alarm.h",
     "include/grpcpp/alarm_impl.h",
     "include/grpcpp/channel.h",
+    "include/grpcpp/channel_impl.h",
     "include/grpcpp/client_context.h",
     "include/grpcpp/completion_queue.h",
     "include/grpcpp/create_channel.h",

CMakeLists.txt

@@ -2985,6 +2985,7 @@ foreach(_hdr
   include/grpcpp/alarm.h
   include/grpcpp/alarm_impl.h
   include/grpcpp/channel.h
+  include/grpcpp/channel_impl.h
   include/grpcpp/client_context.h
   include/grpcpp/completion_queue.h
   include/grpcpp/create_channel.h
@@ -3577,6 +3578,7 @@ foreach(_hdr
   include/grpcpp/alarm.h
   include/grpcpp/alarm_impl.h
   include/grpcpp/channel.h
+  include/grpcpp/channel_impl.h
   include/grpcpp/client_context.h
   include/grpcpp/completion_queue.h
   include/grpcpp/create_channel.h
@@ -4532,6 +4534,7 @@ foreach(_hdr
   include/grpcpp/alarm.h
   include/grpcpp/alarm_impl.h
   include/grpcpp/channel.h
+  include/grpcpp/channel_impl.h
   include/grpcpp/client_context.h
   include/grpcpp/completion_queue.h
   include/grpcpp/create_channel.h

Makefile

@@ -5386,6 +5386,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpcpp/alarm.h \
     include/grpcpp/alarm_impl.h \
     include/grpcpp/channel.h \
+    include/grpcpp/channel_impl.h \
     include/grpcpp/client_context.h \
     include/grpcpp/completion_queue.h \
     include/grpcpp/create_channel.h \
@@ -5987,6 +5988,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpcpp/alarm.h \
     include/grpcpp/alarm_impl.h \
     include/grpcpp/channel.h \
+    include/grpcpp/channel_impl.h \
     include/grpcpp/client_context.h \
     include/grpcpp/completion_queue.h \
     include/grpcpp/create_channel.h \
@@ -6899,6 +6901,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpcpp/alarm.h \
     include/grpcpp/alarm_impl.h \
     include/grpcpp/channel.h \
+    include/grpcpp/channel_impl.h \
     include/grpcpp/client_context.h \
     include/grpcpp/completion_queue.h \
     include/grpcpp/create_channel.h \

build.yaml

@@ -1340,6 +1340,7 @@ filegroups:
   - include/grpcpp/alarm.h
   - include/grpcpp/alarm_impl.h
   - include/grpcpp/channel.h
+  - include/grpcpp/channel_impl.h
   - include/grpcpp/client_context.h
   - include/grpcpp/completion_queue.h
   - include/grpcpp/create_channel.h

gRPC-C++.podspec

@@ -80,6 +80,7 @@ Pod::Spec.new do |s|
     ss.source_files = 'include/grpcpp/alarm.h',
                       'include/grpcpp/alarm_impl.h',
                       'include/grpcpp/channel.h',
+                      'include/grpcpp/channel_impl.h',
                       'include/grpcpp/client_context.h',
                       'include/grpcpp/completion_queue.h',
                       'include/grpcpp/create_channel.h',

tools/doxygen/Doxyfile.c++

@@ -927,6 +927,7 @@ include/grpc/support/workaround_list.h \
 include/grpcpp/alarm.h \
 include/grpcpp/alarm_impl.h \
 include/grpcpp/channel.h \
+include/grpcpp/channel_impl.h \
 include/grpcpp/client_context.h \
 include/grpcpp/completion_queue.h \
 include/grpcpp/create_channel.h \

tools/doxygen/Doxyfile.c++.internal

@@ -928,6 +928,7 @@ include/grpc/support/workaround_list.h \
 include/grpcpp/alarm.h \
 include/grpcpp/alarm_impl.h \
 include/grpcpp/channel.h \
+include/grpcpp/channel_impl.h \
 include/grpcpp/client_context.h \
 include/grpcpp/completion_queue.h \
 include/grpcpp/create_channel.h \

tools/run_tests/generated/sources_and_headers.json

@@ -11309,6 +11309,7 @@
       "include/grpcpp/alarm.h", 
       "include/grpcpp/alarm_impl.h", 
       "include/grpcpp/channel.h", 
+      "include/grpcpp/channel_impl.h", 
       "include/grpcpp/client_context.h", 
       "include/grpcpp/completion_queue.h", 
       "include/grpcpp/create_channel.h", 
@@ -11418,6 +11419,7 @@
       "include/grpcpp/alarm.h", 
       "include/grpcpp/alarm_impl.h", 
       "include/grpcpp/channel.h", 
+      "include/grpcpp/channel_impl.h", 
       "include/grpcpp/client_context.h", 
       "include/grpcpp/completion_queue.h", 
       "include/grpcpp/create_channel.h",