WiFiClient.connected() was hanging thinking there was still a connection when the remote had already closed. The one-liner in this patch addresses recv() returning 0 and errno==128. I couldn't find the corresponding errno for 128 but its caught by the case statement which includes EPIPE, ENOTCONN, ECONNRESET and ECONNABORTED so I assume its one of those. Broken pipe maybe?
```c
[D][WiFiClient.cpp:511] connected(): Disconnected: RES: 0, ERR: 128
```
EDIT: added comment to reflect that recv() can set errno when it returns 0.
* Fix flush
flush should not flush the read buffer, it should wait till all output is drained from the write buffer.
* Update BluetoothSerial.cpp
Co-authored-by: Me No Dev <me-no-dev@users.noreply.github.com>
fixed the connected() function so that it only checks errno if recv returns a value of -1.
"in the even of an error, errno is set to indicate the error" --manpage
This fixes the ESP32 Webserver when dealing with a modern webserver with a slow SD card.
* API compatibility to AVR, ESP8266, et al
* Add non-blocking HardwareSerial::read(buffer, size) extension (ESP8266 portability)
* Refactor for fewer indirect calls.
* Updated BLERemoteCharacteristic to exposre esp_gatt_auth_req_t parameter for readValue and writeValue.
* Updated BLERemoteCharacteristic/Descriptor to expose a setAuth method to allow tweaking the authentication request type for that remotecharacteristic/descriptor without the need to add auth on each read/write.
With the >= used let's say you have four RMT inputs, each using 2 channels wide for their receive buffer. This is 4*2 = 8 buffers which is the number of hardware buffers (MAX_CHANNELS). But, for the fourth input the starting buffer will be 6 (this is correct, the buffers used for each input are 0-1, 2-3, 4-5, 6-7). But, 6+2 = 8 which is MAX_CHANNELS. This is valid but the >= would match against it and abort. It is correct to only abort if the value i+j is only greater than MAX_CHANNELS. Thus, a simple one character fix. Delete the equals sign.
If two headers with overlapping names are added while replace == true, like in:
```cpp
http.addHeader("api_token", "pMXFOLpinQqajaRQJYMeWObg2XYmcX1");
http.addHeader("token", "1234");
```
then replacing went wrong. This is fixed with this PR.
