Passing a float array to a ComputeBuffer within a struct

Question

Working with Unity and a Compute Shader (HLSL). I have a struct, P that I am passing into a computeBuffer which has float fields and those pass just fine, but I'm trying to pass an array of floats buffer as well but whenever I do so I get the error

ArgumentException: Array passed to ComputeBuffer.SetData(array) must be blittable. P.buffer is not blittable because it is not of value type (System.Single[])

According to the docs, primitive arrays are blittable, but how I'm doing it isn't working.

    public struct P{
        . . .
        public float[] buffer; 
        . . .
    }

And then space allocation:

    private void allocateSpaceP(){
        . . .
        int bufferSize = sizeof(float) * arraySize;
        . . .
        
        
        int totalSize = . . . + bufferSize; 

        pBuffer = new ComputeBuffer(pList.Length, totalSize);
        pBuffer.SetData(pList);
        shader.SetBuffer(mainKernal, "P", pBuffer);
        shader.SetBuffer(pKernal, "P", pBuffer);
    }