Revert "chore: use {f32,f64}::from_bits"

This reverts commit 6850c05.

zarrs_metadata/src/v3/array/nan_representations.rs

@@ -2,16 +2,24 @@
 //!
 //! Zarr uses the not-a-number (NaN) value where the sign bit is 0 (positive), the most significant bit (MSB) of the mantissa is 1, and all other bits of the mantissa are zero.
 
+use std::mem::transmute;
+
 use half::{bf16, f16};
 
+// https://github.com/rust-lang/rust/issues/72447
+
 /// The Zarr "NaN" fill value for a 64-bit IEEE 754 floating point number.
 #[allow(clippy::unusual_byte_groupings)]
-pub const ZARR_NAN_F64: f64 =
-    f64::from_bits(0b0_11111111111_1000000000000000000000000000000000000000000000000000);
+pub const ZARR_NAN_F64: f64 = unsafe {
+    transmute::<u64, f64>(0b0_11111111111_1000000000000000000000000000000000000000000000000000)
+};
+// const ZARR_NAN_F64: f64 = f64::from_bits(0b0_11111111111_1000000000000000000000000000000000000000000000000000);
 
 /// The Zarr "NaN" fill value for a 32-bit IEEE 754 floating point number.
 #[allow(clippy::unusual_byte_groupings)]
-pub const ZARR_NAN_F32: f32 = f32::from_bits(0b0_11111111_10000000000000000000000);
+pub const ZARR_NAN_F32: f32 =
+    unsafe { transmute::<u32, f32>(0b0_11111111_10000000000000000000000) };
+// const ZARR_NAN_F32: f32 = f32::from_bits(0b0_11111111_10000000000000000000000);
 
 /// The Zarr "NaN" fill value for a 16-bit IEEE 754 floating point number.
 pub const ZARR_NAN_F16: f16 = f16::NAN;