sqrt

    pub fn sqrt(rma: *Managed, a: *const Managed) !void {
        const bit_count = a.bitCountAbs();
        const aliased = limbsAliasDistinct(rma, a);

        if (bit_count == 0) {
            try rma.set(0);
            rma.setMetadata(a.isPositive(), rma.len());
            return;
        }

        if (!a.isPositive()) {
            return error.SqrtOfNegativeNumber;
        }

        const needed_limbs = calcSqrtLimbsBufferLen(bit_count);
        const limbs_buffer = try rma.allocator.alloc(Limb, needed_limbs);
        defer rma.allocator.free(limbs_buffer);

        const needed = (a.len() - 1) / 2 + 1;
        try rma.ensureAliasAwareCapacity(needed, aliased);
        var m = rma.toMutable();
        m.sqrt(a.toConst(), limbs_buffer);
        rma.setMetadata(m.positive, m.len);
    }