[runtime.Pinner].

The _GoString_ type also may not be pinned with [runtime.Pinner].
Because it includes a Go pointer, the memory it points to is only pinned
for the duration of the call; _GoString_ values may not be retained by C
code.

A Go function called by C code may return a Go pointer to pinned memory
(which implies that it may not return a string, slice, channel, and so

<a href="#Function_literals">function literal</a> or
<a href="#Method_values">method value</a>.
</p>

<p>
It is legal to derive a function value from a method of an interface type.
The resulting function takes an explicit receiver of that interface type.
</p>

<h3 id="Method_values">Method values</h3>

<p>
If the expression <code>x</code> has static type <code>T</code> and

		// Corrupt foo.txt's final crc32 byte, in both
		// the file header and TOC. (0x7e -> 0x7f)
		b[0x11]++
		b[0x9d]++

		// TODO(bradfitz): add a new test that only corrupts
		// one of these values, and verify that that's also an
		// error. Currently, the reader code doesn't verify the
		// fileheader and TOC's crc32 match if they're both
		// non-zero and only the second line above, the TOC,
		// is what matters.

<a href="#Function_literals">function literal</a> or
<a href="#Method_values">method value</a>.
</p>

<p>
It is legal to derive a function value from a method of an interface type.
The resulting function takes an explicit receiver of that interface type.
</p>

<h3 id="Method_values">Method values</h3>

<p>
If the expression <code>x</code> has static type <code>T</code> and

// allowedFormats determines which formats can be used.
// The value returned is the logical OR of multiple possible formats.
// If the value is FormatUnknown, then the input Header cannot be encoded
// and an error is returned explaining why.
//
// As a by-product of checking the fields, this function returns paxHdrs, which
// contain all fields that could not be directly encoded.

behavior has changed based on a non-default value
for that setting.
For example, when `GODEBUG=http2client=0` is set,
`/godebug/non-default-behavior/http2client:events`
counts the number of HTTP transports that the program
has configured without HTTP/2 support.

## Default GODEBUG Values {#default}

When a GODEBUG setting is not listed in the environment variable,
its value is derived from three sources:

canonicalizing values (like "interning" or "hash-consing").

Any value of comparable type may be canonicalized with the new
`Make[T]` function, which produces a reference to a canonical copy of
the value in the form of a `Handle[T]`.
Two `Handle[T]` are equal if and only if the values used to produce the
handles are equal, allowing programs to deduplicate values and reduce
their memory footprint.

// not a value, and the value returned is a pointer to a newly
// allocated zero value of that type.
func new(Type) *Type

// The complex built-in function constructs a complex value from two
// floating-point values. The real and imaginary parts must be of the same
// size, either float32 or float64 (or assignable to them), and the return

Second, the timer channel associated with a `Timer` or `Ticker` is
now unbuffered, with capacity 0.
The main effect of this change is that Go now guarantees
that for any call to a `Reset` or `Stop` method, no stale values
prepared before that call will be sent or received after the call.
Earlier versions of Go used channels with a one-element buffer,
making it difficult to use `Reset` and `Stop` correctly.

			if 'A' <= sr && sr <= 'Z' && tr == sr+'a'-'A' {
				continue
			}
			return false
		}

		// General case. SimpleFold(x) returns the next equivalent rune > x
		// or wraps around to smaller values.
		r := unicode.SimpleFold(sr)
		for r != sr && r < tr {
			r = unicode.SimpleFold(r)
		}
		if r == tr {
			continue
		}
		return false
	}

	// One string is empty. Are both?