https://apple.github.io/servicetalk/servicetalk/SNAPSHOT/javadoc/io/servicetalk/grpc/api/GrpcClientCallFactory.BlockingRequestStreamingClientCall.html
GrpcClientCallFactory.BlockingRequestStreamingClientCall
declaration: package: io.servicetalk.grpc.api, interface: GrpcClientCallFactory, interface: BlockingRequestStreamingClientCall