Function render__update_texture 

pub unsafe extern "C" fn render__update_texture(
    handle: TextureHandle,
    pos_x: u32,
    pos_y: u32,
    width: u32,
    height: u32,
    data_ptr: *const u8,
    data_len: u32,
)

Updates a subrectangle of a texture with new data.

Format is implied to be the same as the texture already is in.