code: func (c *Tracing) Start(categories string, options string, bufferUsageReportingInterval float64, transferMode string, streamCompression string, traceConfig *TracingTraceConfig) (*gcdmessage.ChromeResponse, error) {
  	var v TracingStartParams
  	v.Categories = categories
  	v.Options = options
  	v.BufferUsageReportingInterval = bufferUsageReportingInterval
  	v.TransferMode = transferMode
  	v.StreamCompression = streamCompression
  	v.TraceConfig = traceConfig
  	return c.StartWithParams(&v)
  }
docs: // Start - Start trace events collection.
  // categories - Category/tag filter
  // options - Tracing options
  // bufferUsageReportingInterval - If set, the agent will issue bufferUsage events at this interval, specified in milliseconds
  // transferMode - Whether to report trace events as series of dataCollected events or to save trace to a stream (defaults to `ReportEvents`).
  // streamCompression - Compression format to use. This only applies when using `ReturnAsStream` transfer mode (defaults to `none`) enum values: none, gzip
  // traceConfig -