/*!
@page bigtable-environment-variables Environment Variables Used by the Google Cloud Bigtable C++ Client.

The Cloud Bigtable C++ Client library introduces a single environment variable
that affects its behavior. If `BIGTABLE_EMULATOR_HOST` is set, it specifies the
endpoint (typically a `host:port` string) for the [Cloud Bigtable
emulator](https://cloud.google.com/bigtable/docs/emulator) and configures the
library to connect to the emulator by default.

In addition, the library inherits all the [gRPC environment
variables](https://grpc.io/grpc/cpp/md_doc_environment_variables.html).

@see @link #google::cloud::bigtable::v1::ClientOptions `ClientOptions` @endlink
    for more details of how `BIGTABLE_EMULATOR_HOST` is used.

@see the [gRPC
documentation](https://grpc.io/grpc/cpp/md_doc_environment_variables.html) for
    additional environment variables controlling gRPC.

*/