    const std = @import("../std.zig");
    const assert = std.debug.assert;
    const mem = std.mem;

    context: *const anyopaque,
    writeFn: *const fn (context: *const anyopaque, bytes: []const u8) anyerror!usize,

    const Self = @This();
    pub const Error = anyerror;

    pub fn write(self: Self, bytes: []const u8) anyerror!usize {
        return self.writeFn(self.context, bytes);
    }

    pub fn writeAll(self: Self, bytes: []const u8) anyerror!void {
        var index: usize = 0;
        while (index != bytes.len) {
            index += try self.write(bytes[index..]);
        }
    }

    pub fn print(self: Self, comptime format: []const u8, args: anytype) anyerror!void {
        return std.fmt.format(self, format, args);
    }

    pub fn writeByte(self: Self, byte: u8) anyerror!void {
        const array = [1]u8{byte};
        return self.writeAll(&array);
    }

    pub fn writeByteNTimes(self: Self, byte: u8, n: usize) anyerror!void {
        var bytes: [256]u8 = undefined;
        @memset(bytes[0..], byte);

        var remaining: usize = n;
        while (remaining > 0) {
            const to_write = @min(remaining, bytes.len);
            try self.writeAll(bytes[0..to_write]);
            remaining -= to_write;
        }
    }

    pub fn writeBytesNTimes(self: Self, bytes: []const u8, n: usize) anyerror!void {
        var i: usize = 0;
        while (i < n) : (i += 1) {
            try self.writeAll(bytes);
        }
    }

    pub inline fn writeInt(self: Self, comptime T: type, value: T, endian: std.builtin.Endian) anyerror!void {
        var bytes: [@divExact(@typeInfo(T).Int.bits, 8)]u8 = undefined;
        mem.writeInt(std.math.ByteAlignedInt(@TypeOf(value)), &bytes, value, endian);
        return self.writeAll(&bytes);
    }

    pub fn writeStruct(self: Self, value: anytype) anyerror!void {
        // Only extern and packed structs have defined in-memory layout.

        comptime assert(@typeInfo(@TypeOf(value)).Struct.layout != .Auto);
        return self.writeAll(mem.asBytes(&value));
    }