File arriving in larger than expected size in multipart/form-data

import { z, createRoute } from '@hono/zod-openapi'
import  documentService from 'somewhere'
import { HonoPublicAPIApp } from '../types'
import { routePath } from 'hono/route'

const bodySchema = z.object({
  name: z.string(),
  file: z.file(),
  dateIssued: z.iso.date().pipe(z.coerce.date()).optional(),
  dateExpiry: z.iso.date().pipe(z.coerce.date()).optional()
  ...
})

const route = createRoute({
  method: 'post',
  path: '/v1/documents',
  request: {
    body: {
      content: {
        'multipart/form-data': {
          schema: bodySchema
        }
      }
    }
  },
  responses: {
    200: {
      description: 'Document created successfully',
      content: {
        'application/json': {
          schema: responseSchema
        }
      }
    }
  }
})

export const registerAddDocumentRoute = (app: HonoPublicAPIApp) => {
  app.openapi(route, async (c) => {
    const form = c.req.valid('form')

    const document = await documentService.createDocument({
      file: form.file,
      name: form.name,
      dateExpiry: form.dateExpiry,
      dateIssued: form.dateIssued
      ...
    })

    return c.json({
      data: {
        documentId: document.data?.documentId || ''
      }
    })
  })
}