For porting Zig 0.14 code to Zig 0.15: what is the correct replacement for `readByte()` on a file/reader, and where is it called from?

const a: u16 = 0;
const b: u32 = 0;
switch (a) {
     @intCast(b) => ..., // теперь работает
}

const Enum = enum(u8) { ... };

const c: Enum = ...;
switch (c) {
    @enumFromInt(0) => ..., // теперь работает
}

const Tot = enum {
    a,
    b,

    pub const c: Tot = .a; 
}

switch (...) {
    .b => ...,
    .c => ...
}

switch (...) {
    .a => |_, tag| {} // теперь можно теги ловить в обычной ветке, не только inline 
}

inline fn pageAllocator() Allocator {
    // In tests we use our testing allocator so we can detect leaks.
    if (builtin.is_test) return std.testing.allocator;

    // On non-macOS we use our standard Zig page allocator.
    if (!builtin.target.os.tag.isDarwin()) return std.heap.page_allocator;

    // On macOS we want to tag our memory so we can assign it to our
    // core terminal usage.
    const mach = @import("../os/mach.zig");
    return mach.taggedPageAllocator(.application_specific_1);
}