Push 512 instead of 256 bytes, async socket close

[CptHolzschnauz]

1. The modem is capable to digest 512 bytes per bite to write into a tcp socket. It runs more stable like this, i think the modem expects a full load.
2. From the ublox docs to the new firmware: The +USORD AT command fails to read pending bytes when the socket is in closed state. To avoid the AT command interface hanging, it is recommended to use async socket close, e.g. AT+USOCL=0,1 (the +UUSOCL URC response will take 120 s in thiscase but will not block the AT interface).
   So closing a socket with ,1 (in async mode) will not block the AT interface until the socket is closed

[github-actions]

Memory usage change @ 00e8ae8

Board	flash	%	RAM for global variables	%
arduino:samd:mkrnb1500	🔺 0 - +8	0.0 - 0.0	0 - 0	0.0 - 0.0

Click for full report table

Board	examples/GPRSUdpNtpClient flash	%	examples/GPRSUdpNtpClient RAM for global variables	%	examples/NBSSLWebClient flash	%	examples/NBSSLWebClient RAM for global variables	%	examples/NBWebClient flash	%	examples/NBWebClient RAM for global variables	%	examples/ReceiveSMS flash	%	examples/ReceiveSMS RAM for global variables	%	examples/SendSMS flash	%	examples/SendSMS RAM for global variables	%	examples/Tools/ChooseRadioAccessTechnology flash	%	examples/Tools/ChooseRadioAccessTechnology RAM for global variables	%	examples/Tools/NBScanNetworks flash	%	examples/Tools/NBScanNetworks RAM for global variables	%	examples/Tools/PinManagement flash	%	examples/Tools/PinManagement RAM for global variables	%	examples/Tools/SerialSARAPassthrough flash	%	examples/Tools/SerialSARAPassthrough RAM for global variables	%	examples/Tools/TestGPRS flash	%	examples/Tools/TestGPRS RAM for global variables	%	examples/Tools/TestModem flash	%	examples/Tools/TestModem RAM for global variables	%
arduino:samd:mkrnb1500	8	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	8	0.0	0	0.0	0	0.0	0	0.0

Click for full report CSV

Board,examples/GPRSUdpNtpClient<br>flash,%,examples/GPRSUdpNtpClient<br>RAM for global variables,%,examples/NBSSLWebClient<br>flash,%,examples/NBSSLWebClient<br>RAM for global variables,%,examples/NBWebClient<br>flash,%,examples/NBWebClient<br>RAM for global variables,%,examples/ReceiveSMS<br>flash,%,examples/ReceiveSMS<br>RAM for global variables,%,examples/SendSMS<br>flash,%,examples/SendSMS<br>RAM for global variables,%,examples/Tools/ChooseRadioAccessTechnology<br>flash,%,examples/Tools/ChooseRadioAccessTechnology<br>RAM for global variables,%,examples/Tools/NBScanNetworks<br>flash,%,examples/Tools/NBScanNetworks<br>RAM for global variables,%,examples/Tools/PinManagement<br>flash,%,examples/Tools/PinManagement<br>RAM for global variables,%,examples/Tools/SerialSARAPassthrough<br>flash,%,examples/Tools/SerialSARAPassthrough<br>RAM for global variables,%,examples/Tools/TestGPRS<br>flash,%,examples/Tools/TestGPRS<br>RAM for global variables,%,examples/Tools/TestModem<br>flash,%,examples/Tools/TestModem<br>RAM for global variables,%
arduino:samd:mkrnb1500,8,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,8,0.0,0,0.0,0,0.0,0,0.0