PubSub: gRPC channel memory leak/not closed. #4

Direct leak of 2912 byte(s) in 4 object(s) allocated from:
    #0 0x55e0cdf45ee2 in calloc llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
    googleapis/google-cloud-python#1 0x55e0ce6b7642 in gpr_zalloc grpc/src/core/lib/gpr/alloc.cc:43:7
    googleapis/google-cloud-python#2 0x55e0ce5fafd9 in grpc_channel_stack_builder_finish(grpc_channel_stack_builder*, unsigned long, int, void (*)(void*, grpc_error*), void*, void**) grpc/src/core/lib/channel/channel_stack_builder.cc:292:13
    googleapis/google-cloud-python#3 0x55e0ce68af4a in grpc_channel_create_with_builder(grpc_channel_stack_builder*, grpc_channel_stack_type) grpc/src/core/lib/surface/channel.cc:79:23
    googleapis/google-cloud-python#4 0x55e0ce68bba2 in grpc_channel_create(char const*, grpc_channel_args const*, grpc_channel_stack_type, grpc_transport*, grpc_resource_user*) grpc/src/core/lib/surface/channel.cc:290:7
    googleapis/google-cloud-python#5 0x55e0ce3d7ebf in grpc_core::(anonymous namespace)::CreateChannel(char const*, grpc_channel_args const*) grpc/src/core/ext/transport/chttp2/client/secure/secure_channel_create.cc:169:7
    googleapis/google-cloud-python#6 0x55e0ce3d7ba3 in grpc_secure_channel_create grpc/src/core/ext/transport/chttp2/client/secure/secure_channel_create.cc:217:15
    googleapis/google-cloud-python#7 0x7ff05f195052 in __pyx_pf_7google3_3net_4grpc_6python_7_cython_6cygrpc_7Channel___cinit__(__pyx_obj_7google3_3net_4grpc_6python_7_cython_6cygrpc_Channel*, _object*, _object*, __pyx_obj_7google3_3net_4grpc_6python_7_cython_6cygrpc_ChannelCredentials*) blaze-out/k8-asan-fastbuild/genfiles/net/grpc/python/_cython/cygrpc.pyx_cython_generated.cc:16812:39
    googleapis/google-cloud-python#8 0x7ff05f194578 in __pyx_pw_7google3_3net_4grpc_6python_7_cython_6cygrpc_7Channel_1__cinit__(_object*, _object*, _object*) blaze-out/k8-asan-fastbuild/genfiles/net/grpc/python/_cython/cygrpc.pyx_cython_generated.cc:16602:13
    googleapis/google-cloud-python#9 0x7ff05f17436d in __pyx_tp_new_7google3_3net_4grpc_6python_7_cython_6cygrpc_Channel(_typeobject*, _object*, _object*) blaze-out/k8-asan-fastbuild/genfiles/net/grpc/python/_cython/cygrpc.pyx_cython_generated.cc:64996:7
    googleapis/google-cloud-python#10 0x55e0d3319338 in type_call python_runtime/v2_7/Objects/typeobject.c:749:11
    googleapis/google-cloud-python#11 0x55e0d32ba471 in PyObject_Call python_runtime/v2_7/Objects/abstract.c:2544:18
    googleapis/google-cloud-python#12 0x55e0d3367433 in do_call python_runtime/v2_7/Python/ceval.c:4612:18
    googleapis/google-cloud-python#13 0x55e0d3367433 in call_function python_runtime/v2_7/Python/ceval.c:4417:17
    googleapis/google-cloud-python#14 0x55e0d3367433 in PyEval_EvalFrameEx python_runtime/v2_7/Python/ceval.c:3013:17
    googleapis/google-cloud-python#15 0x55e0d3360e59 in PyEval_EvalCodeEx python_runtime/v2_7/Python/ceval.c:3627:14
    googleapis/google-cloud-python#16 0x55e0d32e7a55 in function_call python_runtime/v2_7/Objects/funcobject.c:523:14
    googleapis/google-cloud-python#17 0x55e0d32ba471 in PyObject_Call python_runtime/v2_7/Objects/abstract.c:2544:18
    googleapis/google-cloud-python#18 0x55e0d32c9c62 in instancemethod_call python_runtime/v2_7/Objects/classobject.c:2600:14
    googleapis/google-cloud-python#19 0x55e0d32ba471 in PyObject_Call python_runtime/v2_7/Objects/abstract.c:2544:18
    googleapis/google-cloud-python#20 0x55e0d331d86f in slot_tp_init python_runtime/v2_7/Objects/typeobject.c:5872:11
    googleapis/google-cloud-python#21 0x55e0d3319448 in type_call python_runtime/v2_7/Objects/typeobject.c:765:13
    googleapis/google-cloud-python#22 0x55e0d32ba471 in PyObject_Call python_runtime/v2_7/Objects/abstract.c:2544:18
    googleapis/google-cloud-python#23 0x55e0d3367433 in do_call python_runtime/v2_7/Python/ceval.c:4612:18
    googleapis/google-cloud-python#24 0x55e0d3367433 in call_function python_runtime/v2_7/Python/ceval.c:4417:17
    googleapis/google-cloud-python#25 0x55e0d3367433 in PyEval_EvalFrameEx python_runtime/v2_7/Python/ceval.c:3013:17
    googleapis/google-cloud-python#26 0x55e0d3360e59 in PyEval_EvalCodeEx python_runtime/v2_7/Python/ceval.c:3627:14
    googleapis/google-cloud-python#27 0x55e0d32e7a55 in function_call python_runtime/v2_7/Objects/funcobject.c:523:14
    googleapis/google-cloud-python#28 0x55e0d32ba471 in PyObject_Call python_runtime/v2_7/Objects/abstract.c:2544:18
    googleapis/google-cloud-python#29 0x55e0d32c9c62 in instancemethod_call python_runtime/v2_7/Objects/classobject.c:2600:14
    googleapis/google-cloud-python#30 0x55e0d32ba471 in PyObject_Call python_runtime/v2_7/Objects/abstract.c:2544:18
    googleapis/google-cloud-python#31 0x55e0d331d86f in slot_tp_init python_runtime/v2_7/Objects/typeobject.c:5872:11
    googleapis/google-cloud-python#32 0x55e0d3319448 in type_call python_runtime/v2_7/Objects/typeobject.c:765:13
    googleapis/google-cloud-python#33 0x55e0d32ba471 in PyObject_Call python_runtime/v2_7/Objects/abstract.c:2544:18```

As can be seen here gRPC channels must be explicitly closes using the close() method. 
[https://github.com/grpc/grpc/issues/12531]

Thanks!

Let me know if you need anymore information!