Missing `NSPageSize` and related functions

[fumoboy007]

In the legacy Foundation module, there are a few useful memory-related functions:

• NSPageSize
• NSRoundUpToMultipleOfPageSize
• NSRoundDownToMultipleOfPageSize

Are they coming to the new FoundationEssentials module?

[itingliu]

We likely won't want to bring these static functions as-is into swift-foundation as they don't really fit into Swift nicely. We could instead consider adding page size as an API to, say, ProcessInfo, since it currently has OS-level API such as physicalMemory?

[fumoboy007]

Good idea!

Perhaps the following names:

• ProcessInfo.virtualMemoryPageSize
• BinaryInteger.round(_:toMultipleOf:)
• BinaryInteger.rounded(_:toMultipleOf:)

Using the rounding APIs would look like

var bytes = …
bytes.round(.up, toMultipleOf: ProcessInfo.processInfo.virtualMemoryPageSize)

Not sure if the rounding APIs should live in Foundation though or somewhere else.