"flat_key","key","int_value","string_value"
"chrome_app_state","chrome_app_state","[NULL]","APP_STATE_FOREGROUND"
"chrome_keyed_service.name","chrome_keyed_service.name","[NULL]","MediaRouter"
"chrome_latency_info.component_info.component_type","chrome_latency_info.component_info[0].component_type","[NULL]","COMPONENT_INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL"
"chrome_latency_info.component_info.time_us","chrome_latency_info.component_info[0].time_us",1201,"[NULL]"
"chrome_latency_info.component_info.time_us","chrome_latency_info.component_info[1].time_us",928310,"[NULL]"
"chrome_latency_info.is_coalesced","chrome_latency_info.is_coalesced",1,"[NULL]"
"chrome_latency_info.trace_id","chrome_latency_info.trace_id",7,"[NULL]"
"chrome_legacy_ipc.message_class","chrome_legacy_ipc.message_class","[NULL]","CLASS_AUTOMATION"
"chrome_legacy_ipc.message_line","chrome_legacy_ipc.message_line",10,"[NULL]"
"chrome_memory_pressure_notification.file_name","chrome_memory_pressure_notification.file_name","[NULL]","another_source.cc"
"chrome_memory_pressure_notification.function_name","chrome_memory_pressure_notification.function_name","[NULL]","AnotherSourceFunction"
"chrome_memory_pressure_notification.line_number","chrome_memory_pressure_notification.line_number",1337,"[NULL]"
"chrome_user_event.action","chrome_user_event.action","[NULL]","NewTab"
"event.category","event.category","[NULL]","cat"
"event.category","event.category","[NULL]","cat"
"event.category","event.category","[NULL]","cat"
"event.category","event.category","[NULL]","cat"
"event.category","event.category","[NULL]","cat"
"event.category","event.category","[NULL]","cat"
"event.name","event.name","[NULL]","name1"
"event.name","event.name","[NULL]","name2"
"event.name","event.name","[NULL]","name3"
"event.name","event.name","[NULL]","name4"
"event.name","event.name","[NULL]","name5"
"event.name","event.name","[NULL]","name6"
"int_extension_for_testing","int_extension_for_testing[0]",42,"[NULL]"
"int_extension_for_testing","int_extension_for_testing[1]",1337,"[NULL]"
"is_root_in_scope","is_root_in_scope",1,"[NULL]"
"nested_message_extension_for_testing.arg1","nested_message_extension_for_testing.arg1","[NULL]","value"
"nested_message_extension_for_testing.arg2.key","nested_message_extension_for_testing.arg2.key","[NULL]","value"
"nested_message_extension_for_testing.child_field_for_testing","nested_message_extension_for_testing.child_field_for_testing","[NULL]","nesting test"
"source","source","[NULL]","descriptor"
"source.file_name","source.file_name","[NULL]","source.cc"
"source.function_name","source.function_name","[NULL]","SourceFunction"
"source.line_number","source.line_number",0,"[NULL]"
"source_id","source_id",1,"[NULL]"
"source_location_iid","source_location_iid",1,"[NULL]"
"string_extension_for_testing","string_extension_for_testing","[NULL]","an extension string!"