docstr: Create a part from a Request Field generated by urllib3.
code: def from_field(cls, field, encoding):
      """Create a part from a Request Field generated by urllib3."""
      headers = encode_with(field.render_headers(), encoding)
      body = coerce_data(field.data, encoding)
      return cls(headers, body)
  
imports: import contextlib
  import io
  import os
  from uuid import uuid4
  import requests
  from .._compat import fields
label_desc: Use image node_id 2 for calling the Part obj's underlying member method code with example usage: obj.from_field(cls, field, encoding) and returns: cls