public void setKeepAliveWithoutCalls(final Boolean keepAliveWithoutCalls) {
        this.keepAliveWithoutCalls = keepAliveWithoutCalls;
    }
Sets whether keepAlive will be performed when there are no outstanding RPC on a connection. Defaults to
{@code false}.

@param keepAliveWithoutCalls whether keepAlive will be performed when there are no outstanding RPC on a
       connection.

@see #setEnableKeepAlive(Boolean)
@see NettyChannelBuilder#keepAliveWithoutCalls(boolean)
grpc-client-spring-boot-starter/src/main/java/net/devh/boot/grpc/client/config/GrpcChannelProperties.java