Response to BTP_L2CAP_SEND_DATA command is already sent in command handler (`send_data()`). Sending further responses to already answered command is confusing - we cannot fail successful procedure retroactively. Data sending is already confirmed to be started successfully and no further responses are expected - more so, it appears to break `available_queue` management and further commands cannot be processed correctly. Similar callback may be proposed in the future if confirmation of sending data is needed, but not in form of BTP response, but BTP event.
Sample applications
advertiser
This is the simplest example of advertising. Application sets NRPA, configures advertisement parameters: general discoverable and not connectable and fills advertisement fields. Transmited data contains only flags, tx power level and device name, which fits in 31B limit of single package. With this data set, device advertises for 10 seconds, terminates advertisement and repeats process again infinitely.
scanner
This application shows how to perform simple scan. Device performs discovery procedure, during which receives advertising reports (if any devices are advertising nearby). These reports are being parsed and results are printed to serial port. Applicaton starts new discovery every second.
peripheral
Peripheral application is based on advertiser, but has added capability of connecting with other devices. As peripheral, device doesn't initiate any connection by itself; instead, advertises infinitely and accepts any connection request it receives. Because we cannot use any 16 or 32 bit UUIDs, as these are reserved by Bluetooth SIG, we are forced to use 128-bit one. Including such long UUID in advertising data consumes large part of available payload, so this data is split in advertising data and response data.
central
This application works in pair with peripheral. It's based on scanner application - the difference is, that if there was detected device with UUID fitting to the one predefined in central application, connection is initiated.