[doc] Document {start,end}_trace
[doc] Document {start,end}_trace

Related to #2

tlunter/oboe-ruby,boyang-li/oboe-ruby,appneta/ruby-traceview,tlunter/oboe-ruby,boyang-li/oboe-ruby,boyang-li/oboe-ruby,tlunter/oboe-ruby,appneta/ruby-traceview,boyang-li/oboe-ruby,appneta/ruby-traceview,appneta/ruby-traceview,tlunter/oboe-ruby