Creating an Mqtt client instance requires several parameters including a unique client ID, a broker IP address and port, and the optional MqttProperties object described previously.

创建Mqtt客户实例需要几个参数，包括一个惟一客户机id、代理ip地址和端口以及可选的MqttProperties对象。

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DB9M-to-USB cable (optional if your host platform has an RS-232 port).

DB9M - to - US b线缆(如果主机平台有RS - 232端口，它就是可选的)。

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The firm plans to offer optional solar-photoelectric systems, to be set up as a car port at home, that will be able to power the cars for 80km a day without having to draw on the grid.

公司计划提供光电转能系统，即未来的太阳能车房能实现电驱车不必从电网取电一天跑80公里了。

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Both the LIFEBOOK E752 and LIFEBOOK S752 notebooks support up to three active displays with the Optional Port Replicator -- increasing productivity for multitasking users.

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Its multiroom audio capabilities are similarly extensive with Powered Zone 2 and 3 capabilities, multiple DC triggers, bidirectional RS-232, and Onkyo's exclusive Universal Port for connection of an optional iPod Dock and HD Radio tuner.

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Down at the base, you'll find a proprietary charging port between two notches for the optional keyboard dock.

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