Help with lazy loading lsp server

[mainendra]

LSP server setup is taking 50% startup time. I'm trying to lazy load server but getting nil server name when using automatic server setup.

mason_lspconfig.setup_handlers({
  function (server_name)
    lspconfig[server_name].setup {
      on_attach = on_attach
    }
  end
})

I'm using lazy.nvim

    {
        'neovim/nvim-lspconfig',
        event = 'BufReadPre',
        dependencies = {

            'williamboman/mason.nvim',
            'williamboman/mason-lspconfig.nvim',
        },
        config = function()
            local mason = require('mason')
            local mason_lspconfig = require('mason-lspconfig')
            mason.setup()
            mason_lspconfig.setup({
                ensure_installed = { 'lua_ls' },
                automatic_installation = true
            })
            mason_lspconfig.setup_handlers({
                function (server_name)
                    lspconfig[server_name].setup {
                        on_attach = on_attach
                    }
                end
            })
        end

    }

[mainendra]

It was issue with file name. I was using lspconfig.lua file name to setup handler (after/plugin/lspconfig.lua) and moved that under nvim/lua/lspconfig.lua. After renaming it to lsp.lua it started working. Thanks.