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.

The default value is 0 (= all channels) to preserve backward compatibility.

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.

`WIFI_REASON_CONNECTION_FAIL` has been added to `wifi_err_reason_t` some time ago:  
https://github.com/espressif/arduino-esp32/blob/cec3fca4ad4a39feb463f9298ab3238819732d50/tools/sdk/include/esp32/esp_wifi_types.h#L95

But it was still missing from `system_event_reasons` in `WiFiGeneric.cpp` sometimes causing panics here:  
https://github.com/espressif/arduino-esp32/blob/cec3fca4ad4a39feb463f9298ab3238819732d50/libraries/WiFi/src/WiFiGeneric.cpp#L348

This event name was missing in the list:
https://github.com/espressif/arduino-esp32/blob/d5e2bb12ca02ae9066e9dad84d9dbf268aca6fa3/tools/sdk/include/esp32/esp_event_legacy.h#L43

E.g., it was giving
[D][WiFiGeneric.cpp:337] _eventCallback(): Event: 24 - ETH_GOT_IP
When it should have been
[D][WiFiGeneric.cpp:337] _eventCallback(): Event: 24 - ETH_DISCONNECTED

* Add support for WiFi long range mode

* Update WiFiGeneric.cpp

Add an accessor function for the useful wifi data

* Added timeout to WiFiScan class to prevent haning at stucking at WIFI_SCAN_RUNNING when scan fails internally

* fixed tabs and returns, connected scanTimeout to max_scan_per_channel timeout

* Corrected tabs two

* Added static vars scanTimeout und scanStarted to WiFiScan.h protected section

* Fixed missing ; in line 64

Relative to #3006

* Add generic IP calculations

Add:
calculateNetworkID(IPAddress ip, IPAddress subnet) => Calculate the network id using the ip and subnet (e.g. 192.168.0.0)
calculateBroadcast(IPAddress ip, IPAddress subnet) => Calculate the broadcast ip using the ip and subnet (e.g. 192.168.0.255)
calculateSubnetCIDR(IPAddress subnetMask) => Calculate the subnet CIDR using the subnet (e.g. 24)

Add:
broadcastIP() => Retrieve the network id (e.g. 192.168.0.0)
networkID() => Retrieve the broadcast IP (e.g. 192.168.0.255)
subnetCIDR() => Retrieve the subnet CIDR (e.g. 24)

Add:
broadcastIP() => Retrieve the network id (e.g. 192.168.0.0)
networkID() => Retrieve the broadcast IP (e.g. 192.168.0.255)
subnetCIDR() => Retrieve the subnet CIDR (e.g. 24)

Add:
softAPBroadcastIP() => Retrieve the network id (e.g. 192.168.0.0)
softAPNetwrokID() => Retrieve the broadcast IP (e.g. 192.168.0.255)
softAPSubnetCIDR() => Retrieve the subnet CIDR (e.g. 24)

* Config fix test

* Also force config even if equal

* WiFiClient.cpp - Fix connect() behavior

* lwip_connect_r() : check return code

* Use macros for switch case labels

* Fixed spelling error in "too"

* Fix spacing

* Inline private functions that are only called once

* add opportunity for more than one retry to _uploadReadByte

* an alternative timeout-based method to making _uploadReadByte more resilient

* move timing variables in the correct scope

* implement and use client.getTimeout instead of hard-coded timeout in _uploadReadByte

* add missing return

* some refactoring to address respecting the timeout in a potentially deadlocked connection

* fix spelling in comment

* address review comments; move impl to cpp file for getTimeout, and remove local variable for currentMillis

* remove redundant cast

* need to check for timeout outside the inner while as well

* update WebUpdate example to print something in unexpected callback condition

* update log_e messages per review comments

Currently  WiFiClient::write is unable to send messages over 25Kb, because of the hard-coded retry limit of 10, that is getting decremented on every successful send. Since we cannot send more than 2*MTU bytes in one go, and have only 10 retries, write() is limited to approximately 25Kb. Technically it is not a bug, as it correctly returns the number of sent bytes and the caller can set up futher retries. But not all libs are aware of this behavior, for example, WebServer is not.
I suggest improving current behavior by resetting retry counter every time we had a successful write, so the limit of 10 retries will apply to Failed writes only, and will not apply to Successful writes. This will allow to write() blobs of arbitrary sizes.

* WiFi.macaddress() returns mac address

* change description

* return macaddress when WiFi mode is WIFI_MODE_NULL

* Add timeout to WiFiClient.connect()

* Changed default handling

* fix log error code format

* remove useless condition in if statement

Fixes https://github.com/espressif/arduino-esp32/issues/1595

Fix error in PR #2048: if ::available() is called before ::connect() _rxBuffer is not initialised (#2155)

#2147 available() shouldn't return 0 after disconnect if there is still data in the buffer. Otherwise, how would we know it was there? (#2148)

* Use right function for BSSID

* removing log

* Clean warnings when all warning enabled

Not used variables / functions due to debug log

Dual define with different values :
cores\esp32/binary.h
#define B110 6
#define B1000000 64

tools/sdk/include/newlib/sys/termios.h
#define B110        3
#define B1000000   23

Local variable returned in WiFiclient Secure

* change due to deprecated function

* Update with proper variable and label

* Update esp32-hal-i2c.c

* Apply changes requested

* Fix warnings due to #define conflict thanks @atanisoft

* Pass client parameter into two new begin() functions. Set other begin() functions deprecated. Updated library version to 1.2

* Added working HTTPS example on a public url with a certificate

* Remove two unnecessary tests in ::disconnect()

* Add a scoping block to BasicHttpsClient.ino to assure HTTPClient is destroyed before WiFiClientSecure

* Added check to handle mixup of old and present api properly

* Correct HTTPClient::setTimeout() to convert milliseconds to seconds. Correct WiFiClient::setTimeout() to call Stream::setTimeout() with seconds converted back to milliseconds. Remove inproper checks for _insecure.

* Added small comment because it looked like the Travis build did not finish

* make WiFi.softAP() more robust

* WiFi.softAP() revert fallback to WIFI_AUTH_OPEN

* TX Flow Control and Code cleanup

* Use semaphore instead of delay

TX functionality is done.

* Use single buffer and empty queue on exit

* Fix compile issues because of LwIP code relocation

* Add temporary header to fix Azure not compiling

* Fix AsyncUDP early init

* AsyncUDP Multicast fixes

* Add source mac address and rework multicast

* Allow redefinition of default pins for Serials 1 and 2

* Update IDF to 3276a13

* Update esptool.py to 2.5.0

* Fix sketches

* Fix log level in BluetoothSetial