Set a variable on a channel. If value is omitted, the variable is unset.
<uuid>
参数说明：
uuid：通话的唯一标识符（通过“show
channels”可查看到）uuid_setvar <uuid> <varname> [value]Dialplan equivalent
<action application="set" data="<varname>=<value>"/>
<!-- For example: -->
<action application="set" data="playback_terminators=none"/> uuid_setvar c2746178-ab61-11ea-86b8-311ce82e049e record_sample_rate 8000