[foreign-memaccess] on endianness

[Maurizio Cimadamore]

Hi,
currently, the memory access prototype uses native endianness where not 
specified. I think that is slightly undesirable, as it makes things 
implicit (and against our design principles); this is particularly 
evident when interacting with byte buffers, which have BIG_ENDIAN by 
default.

So, I think we have a number of choices:

1) endianness should always be explicit
2) allow implicit endianness  - but what is the default value?
    a) BIG_ENDIAN, as for byte buffers (users will have less surprises?)
    b) native, in name of simplifying interaction with native code
    c) some magic NO_ENDIAN state, which will have to be set later 
(before memory access)

I'm currently (strongly) leaning for (1). This option is explicit, and 
correct, and leaves the door open to adding more convenient 
endianness-less defaults in the future. This choice would affect both 
the Layout API (e.g. ValueLayout factories) and the VarHandle 
combinators under MemoryAccessVarHandles.

Comments?

Maurizio