Feature Flags

This page documents the platform FeatureFlags (FeatureFlags::Flags) defined in internal/platform/feature_flags.h and their default values. These flags control runtime behavior used across mediums, BWU logic, multiplexing, and other platform behaviors.

How to access

• Read: FeatureFlags::GetInstance().GetFlags()
• Override for tests: FeatureFlags::GetMutableFlagsForTesting() or FeatureFlags::SetFlags(const Flags&)

Flags (name = default) with brief notes

General

• enable_cancellation_flag = true Controls whether cancellation flag support is enabled.
• enable_async_bandwidth_upgrade = true Allow asynchronous bandwidth upgrade flows.
• cancel_waits_for_running_tasks = true If a scheduled runnable is already running, Cancel() will synchronously wait for task completion.
• keep_alive_interval_millis = 5000
• keep_alive_timeout_millis = 30000 Keep-alive interval/timeout (ms).

Bandwidth upgrade (BWU)

• use_exp_backoff_in_bwu_retry = true If true, BWU retries use exponential backoff.
• bwu_retry_exp_backoff_initial_delay = 3s
• bwu_retry_exp_backoff_maximum_delay = 300s
• enable_send_payload_offset = true Support starting file/stream payloads at a non-zero offset.
• support_multiple_bwu_mediums = true Better bookkeeping to support multiple BWU mediums and endpoints.
• enable_async_bandwidth_upgrade = true

Bluetooth / Connection

• enable_set_radio_state = false Allow code to change bluetooth radio state (disabled by default).
• enable_connection_timeout = true Medium connection will timeout when unable to connect within a duration.
• enable_bluetooth_connection_status_track = true Track Bluetooth Classic connection status.
• enable_scan_for_fast_pair_advertisement = false Enable BLE scan for Fast Pair advertisement UUID (0x2cfe).
• skip_service_discovery_before_connecting_to_rfcomm = false Skip SDP check when connecting over RFCOMM (Windows workaround).
• enable_ble_v2_async_scanning = false Use async StartScanning/StopScanning for BLE V2.
• enable_invoking_legacy_device_discovered_cb = false Enable legacy discovered-device callback inside BLE V2 flow.

Safe-to-disconnect / auto-reconnect / ack behavior

• min_nc_version_supports_safe_to_disconnect = 1
• min_nc_version_supports_auto_reconnect = 3
• safe_to_disconnect_reconnect_retry_delay_millis = 4000ms
• safe_to_disconnect_reconnect_timeout_millis = 15000ms
• safe_to_disconnect_reconnect_retry_attempts = 3
• safe_to_disconnect_skip_duplicated_endpoint_duration = 2000ms
• min_nc_version_supports_payload_received_ack = 6
• safe_to_disconnect_ack_delay_millis = 30000ms
• safe_to_disconnect_remote_disc_delay_millis = 10000ms
• safe_to_disconnect_auto_resume_timeout_millis = 60000ms
• wait_payload_received_ack_millis = 1000ms

Multiplexing / Mediums

• mediums_frame_read_timeout_millis = 15000ms
• mediums_frame_write_timeout_millis = 15000ms
• multiplex_socket_connection_response_timeout_millis = 3000ms
• multiplex_socket_middle_priority_queue_capacity = 50
• connection_max_frame_length = 1048576
• blocking_queue_stream_queue_capacity = 10
• support_web_rtc_non_cellular_medium = false

Related flags and readers

• NearbyFlags is a separate flag reader used throughout the Connections code (see internal/flags/nearby_flags.h and default_flag_reader.h). Use NearbyFlags::GetInstance() to query and override boolean/int/string flags when necessary.

References

• internal/platform/feature_flags.h
• internal/flags/nearby_flags.h
• internal/flags/default_flag_reader.h