FixedBufferStream: match file semantics more by clamping pos
FixedBufferStream: match file semantics more by clamping pos

raulgrell/zig,zig-lang/zig,raulgrell/zig,andrewrk/zig,zig-lang/zig,zig-lang/zig,raulgrell/zig,raulgrell/zig,andrewrk/zig,raulgrell/zig