| "flat_key","key","int_value","string_value" |
| "chrome_histogram_sample.name","chrome_histogram_sample.name","[NULL]","histogram_name1" |
| "chrome_histogram_sample.name","chrome_histogram_sample.name","[NULL]","histogram_name2" |
| "chrome_histogram_sample.name_hash","chrome_histogram_sample.name_hash",10,"[NULL]" |
| "chrome_histogram_sample.name_hash","chrome_histogram_sample.name_hash",20,"[NULL]" |
| "chrome_histogram_sample.name_hash","chrome_histogram_sample.name_hash",30,"[NULL]" |
| "chrome_histogram_sample.sample","chrome_histogram_sample.sample",100,"[NULL]" |
| "event.category","event.category","[NULL]","cat1" |
| "event.category","event.category","[NULL]","cat2" |
| "event.category","event.category","[NULL]","cat3" |
| "event.name","event.name","[NULL]","slice1" |
| "event.name","event.name","[NULL]","slice2" |
| "event.name","event.name","[NULL]","slice3" |
| "is_root_in_scope","is_root_in_scope",1,"[NULL]" |
| "source","source","[NULL]","descriptor" |
| "source_id","source_id",12345,"[NULL]" |
