Reproduction steps:
1. Open the attached project.
2. Make sure Scripting Backend is set to IL2CPP and Scripting Runtime Version is set to .NET 4.6.
3. Build and run on iOS device.
- Application crashes:

* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x18)
* frame #0: 0x000000010162d2e4 t`il2cpp::icalls::System::System::Net::Sockets::Socket::GetSocketOptionObj(socket=<unavailable>, level=kSocketOptionLevelSocket, name=<unavailable>, obj_val=0x000000016fdf8d00, error=<unavailable>) at Socket.cpp:632 [opt]
frame #1: 0x00000001005da1c0 t`::Socket_GetSocketOption_obj_internal_m2691936686(__this=0x0000000000000000, ___socket0=(___m_value_0 = 0x0000000000000003), ___level1=65535, ___name2=128, ___obj_val3=0x000000016fdf8d00, ___error4=0x000000016fdf8d0c, method=0x0000000000000000) at Bulk_System_4.cpp:32525
frame #2: 0x00000001005da0e4 t`::Socket_GetSocketOption_obj_internal_m3103729294(__this=0x0000000000000000, ___safeHandle0=0x000000010775f500, ___level1=65535, ___name2=128, ___obj_val3=0x000000016fdf8d00, ___error4=0x000000016fdf8d0c, method=0x0000000000000000) at Bulk_System_4.cpp:32478
frame #3: 0x00000001005c894c t`::Socket_GetSocketOption_m635580351(__this=0x0000000107748c60, ___optionLevel0=65535, ___optionName1=128, method=0x0000000000000000) at Bulk_System_4.cpp:32374
frame #4: 0x00000001005d05c0 t`::Socket_get_LingerState_m1282755370(__this=0x0000000107748c60, method=0x0000000000000000) at Bulk_System_4.cpp:28111
frame #5: 0x0000000100036980 t`::SocketTest_Awake_m443383255(__this=0x0000000107761e70, method=0x00000001508866e0) at Bulk_Assembly-CSharp_0.cpp:1109
...

Reproduced with:
iOS IL2CPP .NET 4.6
2017.1.0b1, 2017.3.0b1

Not reproducible with:
iOS IL2CPP .NET 3.5
macOS Mono .NET 4.6

Note:
Full callstack attached in the edit.